soc: qcom: Remove bogus depends on OF from QCOM_SMD_RPM

QCOM_SMD_RPM builds perfectly fine without CONFIG_OF set.
Remove the bogus depends on OF.

Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>