clk: qcom: Move prepare enable parent sources for FORCE_ENABLE_RCGR

Move preparing/unpreparing the clock source parents from the clk set rate.
This is required as invoking prepare from clk enable with disable irqs and
prepare would take a mutex resulting in sleeping from invalid context.

Change-Id: I90d8a346f684747f635bd9e7254ceb8d45841b05
Signed-off-by: Taniya Das <tdas@codeaurora.org>