msm_bus: Use clk_set_rate() instead of clk_set_min_rate()

clk_set_min_rate() is a non-standard API which is being phased out
globally and replaced by the standard clk_set_rate().

Change-Id: I7d0fecd88cd3abcba2c7753a04fb0e53672ea998
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>