jtagv8-mm: fix etm registers save and restore sequence

Restore the ETM register that programs enabling the trace unit on
coming out of power collapse only after all other ETM registers
have been restored which is the recommended sequence of programing
the trace unit. Also ensure save and restore is done for all needed
ETM registers which lose their states on power collapse.

Change-Id: Iacbf22d7982508907466b45086791f7b18db90cd
Signed-off-by: Aparna Das <adas@codeaurora.org>