msm: pil-pronto: Implement Secure PIL support

Use scm-pas to detect if Secure PIL is required and if it is,
call scm-pas APIs to boot and shutdown the Pronto Processor
instead of handling these procedures in the Linux Kernel.

Change-Id: I0c9310a2138b522dca408365b506d3eeca966326
Signed-off-by: Tianyi Gou <tgou@codeaurora.org>