rpmsg: glink: Add reset status

Add a status for remote processor reset. Change the intent completion
variable to a waitqueue to check both intent request completion and
processor reset status. This allows rpmsg to cancel threads that are
waiting to send to the remote procssor.

Change-Id: Ic43a8d836f347ab26daec7f906a9a1b0f585a549
Signed-off-by: Chris Lew <clew@codeaurora.org>