clk: qcom: rcg: Return failure for RCG update

In case of update config failure, return -EBUSY, so that consumers could
handle the failure gracefully.

Signed-off-by: Taniya Das <tdas@codeaurora.org>
Link: https://lkml.kernel.org/r/1557339895-21952-2-git-send-email-tdas@codeaurora.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>