soc: qcom: smd: Correct compile stub prototypes

The prototypes for the compile stubs was not properly marked as static
inline, this patch corrects this.

Fixes: f79a917e

 ("Merge tag 'qcom-soc-for-4.7-2' into net-next")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>