msm: clock-8960: cleanup common_clock_post_init for post-init

new functions introduced:
1) msm8960_clock_post_init() --> common for 8960/8930
2) msm8064_clock_post_init() --> 8064
3) common_clock_post_init()  --> This takes care of the post
init of setting the clock rates.

Change-Id: If337d9c840a86999f94299eb10971ae2ee032392
Signed-off-by: Taniya Das <tdas@codeaurora.org>