msm: spm-v2: Flush the PMIC_DATA registers

Different versions of SAW use different PMIC_DATA registers to
save the current voltage, which is used to restore voltage when
exiting low power modes. Flush the appropriate PMIC_DATA registers
depending on the SAW versions.

Change-Id: I7b421ed7e60ebde7c1f9ef32ce1a047ca361c32c
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>