msm: pm-boot: Compile "msm_pm_write_boot_vector" always

Currently "msm_pm_write_boot_vector" is under CONFIG_MSM_SCM
configuration. Which is true for targets having TZ. But this
functionality is required for 8625 traget as well hence moving
this function outside of the configuration.

Change-Id: Ia37f2688525d22e4c463cb10b75badcb1a6ed442
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>