msm: vidc: Add debugfs support to debug timeout issues

This change asserts in the kernel whenever vidc driver times out
waiting for command completion from firmware. This will help to
debug such timeout issues.

Debug timeout can be enabled using the following debugfs
handle - /d/msm_vidc/debug_timeout

Change-Id: I218597f8b5ad0cb89c621f01132bcb669983df2b
Signed-off-by: Sowmya Pandiri <spandiri@codeaurora.org>