msm: clock: Enforce voltage requirements when using clk_set_min_rate()

A couple drivers may use the clk_set_min_rate() API to set rates.
Prior to the voltage scaling reorg in commit e18bbc83, this API
enforced voltage constraints.  It no longer does. Restore this
behaviour.

Change-Id: Ia80fef0b30b940830d024e087591e25e6e1c62b4
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>