lpm-levels: Disable RIMPS timer based PLL/RAIL feature timer

This patch disables the RIMPS timer based PLL/RAIL trigger
timer in core C4 exit so that it stops the RIMPS from ticking
timer when core C4 exit happen before this timer expires.

Change-Id: I74b3e2222dc3ef5ba0fdebd71b7e86201016fc42
Signed-off-by: Raghavendra Kakarla <rkakarla@codeaurora.org>