clk: msm: clock-cpu-8996: Allow interrupts during alt_pll set_rate

The CPU that is disabling the alternate PLL may also need to
handle CPR interrupts. Allow the CPU to handle interrupts
during the set_rate operation.

CRs-Fixed: 960701
Change-Id: I63d7ce3e3dd2b559c4db383b64faa9335c404576
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>