Make the BL3-1 crash reporting optional

This patch makes the console crash dump of processor register
state optional based on the CRASH_REPORTING make variable.

This defaults to only being enabled for DEBUG builds. This can
be overridden by setting a different value in the platform
makefile or on the make command line.

Change-Id: Icfa1b2d7ff0145cf0a85e8ad732f9cee7e7e993f