run: split native Genode netperf script

Split the netperf run script into 3 ones so that it can be used more easily
in an automated run.

netperf.run        - use native nic driver (x86) or usb2.0 (arndale, panda)
netperf_usb30.run  - use native nic driver (x86) or usb3.0
netperf_bridge.run - use native nic driver (x86) or usb3.0 (arndale) and bridge

Issue #794
run: check for netperf version in user environment

For L4linux version on foc_arndale.
run: split netperf l4linux script

Split the netperf run script into 3 ones so that it can be used more easily
in an automated run.

It is solely for foc_arndale by now.

l4linux_netperf.run        - use nic via usb2.0
l4linux_netperf-usb30.run  - use nic via usb3.0
l4linux_netperf-bridge.run - use nic via usb3.0 + bridge
run: prepare netperf l4lx output for post processing
run: add netperf tests to autopilot list

* native Genode (using lwIP) netperf
as
* L4Linux netperf
base-hw: disable L2 cache on Pandaboard (fix #797)

* Fix bitfield typo in TTBR0 register for ARMv7
run: check size of reported disc in part_blk

Triggers bug if LBA48 mode is used.

Issue #761
atapi_drv: Implement LBA48 specific block count

Use NATIVE MAX ADDRESS EXT to retrieve last block for LBA48. Also check not only
for enabled LBA48 support but for the 'host protected area' bit before using the
LBA48 version. This is because the high order byte (HOB) data retrieval is
broken in Qemu.

Fixes issue #761
Add -mcpu flag to ARM CPU spec files (Ref #797)

When using certain assembler instructions, e.g. 'smc' that are
only available on some CPUs of the same architecture like ARMv7a,
it's necessary to specify the target CPU for the assembler. Otherwise
it will complain about.