ENGR00225912 ARM: etm: Add trace buffer support

ENGR00225912 ARM: etm: Add trace buffer support

start trace:
	echo 1 > echo 1 >/sys/devices/etm.0/trace_running

Notes:	The other cores ptm also enabled by above command.

dump trace buffer:
	echo v >/proc/sysrq-trigger

Decode trace buffer:
	/unit_test/etm --pft-1.1 --sourceid-match 0 < /dev/tracebuf

Notes: this version need connect JTAG to make etm work.

Signed-off-by: Frank Li <Frank.Li@freescale.com>