cpu: Remove incorrect branch predictor drain checks

The branch predictor unit incorrectly checked that the prediction
history was empty when the system is drained. This is an incorrect
assumption since the predictor isn't affected by a drain.
cpu: Set memReq[tid] to NULL in finishTranslation after squashes

DefaultFetch::finishTranslation() sometimes deleted the incomming
memory request without clearing the associated memReq pointer. This
caused an assertion in DefaultFetch::drainSanityCheck to fail.
base: Make the Python module loader PEP302 compliant

The custom Python loader didn't comply with PEP302 for two reasons:

 * Previously, we would overwrite old modules on name
   conflicts. PEP302 explicitly states that: "If there is an existing
   module object named 'fullname' in sys.modules, the loader must use
   that existing module".

 * The "__package__" attribute wasn't set. PEP302: "The __package__
   attribute must be set."

This changeset addresses both of these issues.
dev: Clean up MC146818 register (A & B) handling

Rewrite reg A & B handling to use the bitunion stuff instead of bit
masking. Add better error messages when the kernel tries to enable
unsupported stuff.
dev: Add support for disabling ticking and the divider in MC146818

Some Linux versions disable updates (regB.set = 1) to prevent the chip
from updating its internal state while the OS is updating it. Support
for this was already there, this patch merely disables the check in
writeReg that prevented it from being enabled. The patch also includes
support for disabling the divider, which is used to control when clock
updates should start after setting the internal RTC state.

These changes are required to boot most vanilla Linux distributions
that update the RTC settings at boot.
sim: Add support for m5fail in pseudoInst()
kvm: Make MMIO requests uncacheable

Device accesses are normally uncacheable. This change probably doesn't
make any difference since we normally disable caching when KVM is
active. However, there might be devices that check this, so we'd
better enable this flag to be safe.
kvm: Add checkpoint debug print

Add a debug print (when the Checkpoint debug flag is set) on serialize
and unserialize. Additionally, dump the KVM state before
serializing. The KVM state isn't dumped after unserializing since the
state is loaded lazily on the next KVM entry.
arch: Create a method to finalize physical addresses in the TLB

Some architectures (currently only x86) require some fixing-up of
physical addresses after a normal address translation. This is usually
to remap devices such as the APIC, but could be used for other memory
mapped devices as well. When running the CPU in a using hardware
virtualization, we still need to do these address fix-ups before
inserting the request into the memory system. This patch moves this
patch allows that code to be used by such CPUs without doing full
address translations.
kvm: Use the address finalization code in the TLB

Reuse the address finalization code in the TLB instead of replicating
it when handling MMIO. This patch also adds support for injecting
memory mapped IPR requests into the memory system.
kvm: Fix the memory interface used by KVM

The CpuPort class was removed before the KVM patches were committed,
which means that the KVM interface currently doesn't compile. This
changeset adds the BaseKvmCPU::MemPort class which derives from
MasterPort. This class is used on the data and instruction ports
instead of the old CpuPort.