msm: clock: Return error upon invalid call to clk_set_rate.

Calls to clk_set_rate should only change the voltage vote if the clock
is prepared. However, they need to check if the rate is valid even if
the clock is not prepared.

Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
(cherry picked from commit c009d9efe966f1f2ac300d43895bb448a9d27cc0)

Signed-off-by: Dhivya Subramanian <dthiru@codeaurora.org>
(cherry picked from commit 8b5d9d1b3b75cf42df5cf1faeda029ebfbdd308e)

Change-Id: I3a80401dcf76314441ad7624c69433c0ea1d1efe
Signed-off-by: Sudhir Sharma <sudsha@codeaurora.org>