remoteproc/mediatek: unprepare clk if scp_before_load fails

Fixes the error handling to unprepare clk if scp_before_load fails.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Fixes: fd0b6c1f ("remoteproc/mediatek: Add support for mt8192 SCP")
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20201203155914.3844426-1-tzungbi@google.com


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>