msm: pm-boot: flush msm_pm_boot_vector to main memory

msm_pm_boot_vector array stores cores warmboot entry before
cores enter into LPM mode. These warm boot entries must be
visible to core when it comes out of LPM mode. To ensure
this variable to appear in main memory use flush APIs to
flush out of caches. Use a different API to do this on
latest ARM based targets.

Change-Id: I870b68e4f6f6b116e93deffe59edff9094db0fa8
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>