msm: vidc: Handle STREAMON failure in vidc driver

If start_streaming() fails due to some reason,
rc is getting overwritten and error is not propagated
to client resulting hang in driver.
This change fixes the issue for decoder/encoder use case.

Change-Id: Iefa045b3eae89b33717bc9a8ae5185a850a3a976
Signed-off-by: Sowmya Pandiri <spandiri@codeaurora.org>