cpuidle: lpm-levels: Log power state id into lpm debug

lpm driver sends the power state id information to PSCI
framework to do LPMs. Log this information into lpm debug
array. This is information is very useful to root cause
the stability issues from the power front.

Change-Id: Id797b6c7aa79a4c78f9373c7fd0a5f258a50b108
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>