msm: cpufreq: Remove redundant check in cpu_set_freq

Recent code refactoring has led to the unintentional consequence
of having redundant checks for the success of clk_set_rate. Remove
the redundant check.

Change-Id: I6cb7bdec15afb833519fac3232836ce9445cba48
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>