Implement an assert() callable from assembly code

The patch implements a macro ASM_ASSERT() which can
be invoked from assembly code. When assertion happens,
file name and line number of the check is written
to the crash console.

Fixes ARM-software/tf-issues#95

Change-Id: I6f905a068e1c0fa4f746d723f18df60daaa00a86
Rework the crash reporting in BL3-1 to use less stack

This patch reworks the crash reporting mechanism to further
optimise the stack and code size. The reporting makes use
of assembly console functions to avoid calling C Runtime
to report the CPU state. The crash buffer requirement is
reduced to 64 bytes with this implementation. The crash
buffer is now part of per-cpu data which makes retrieving
the crash buffer trivial.

Also now panic() will use crash reporting if
invoked from BL3-1.

Fixes ARM-software/tf-issues#199

Change-Id: I79d27a4524583d723483165dc40801f45e627da5
Add CPUECTLR_EL1 and Snoop Control register to crash reporting

This patch adds the CPUECTLR_EL1 register and the CCI Snoop Control
register to the list of registers being reported when an unhandled
exception occurs.

Change-Id: I2d997f2d6ef3d7fa1fad5efe3364dc9058f9f22c