msm: krait-regulator: disable retention mode if pmic voltage falls
msm: krait-regulator: disable retention mode if pmic voltage falls

LDO path is always employed while a given Krait core is in retention mode.
For LDO mode to be operational it needs the input (pmic voltage) higher
than the output (retention voltage) by the headroom value.

If it falls below, disable retention mode on all the cpus.

Change-Id: Ib338d01fed96c6e914b221cc250a682adec48c02
Signed-off-by: Abhijeet Dharmapurikar <98996d53ce579fa37f08d0061abc5355e223c79e@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas