Revert "soc: qcom: rpmh: Allow RPMH driver to be loaded as a module"

Attempting to compile rpmh-rsc.c as a module with TRACING enabled causes
a build error as no _rcuidle function is generated for tracepoints when
CONFIG_MODULE is set.

Attempts has been made, but no resolution has been agreed upon, so lets
revert this commit for now.

This reverts commit 1d3c6f86.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>