ARM: mach-msm: scm: Add scm_is_call_available api

Add the scm_is_call_available() api to be able to test for existance of certain
functionality.
rproc: Add Qualcomm Peripheral Image Loader driver

Add a quick port of the Qualcomm PIL to drivers/remoteproc. It's possible to
load the wcnss firmware with this implementation. Further restructuring and
cleanup with the goal of getting this into the remoteproc framework needs to be
done.