lpm-levels: Add RIMPS timer base rail/PLL turn off functionality

This patch adds the logic to enable the RIMPS timer based
rail-pc trigger functionality. This patch programs the RIMPS
timer when each core of corresponding clock domain entering
into the rail-pc LPM and enables the RIMPS timer feature so
that RIMPS allows to turn off rail/PLL based on the timer
threshold and timeout values.

Change-Id: Ib3589933d339a7224147a7c7afc006f260d8205b
Signed-off-by: Raghavendra Kakarla <rkakarla@codeaurora.org>