slim: msm: Improve bulk message timeout error handling

If a bulk message times out due to interrupt starvation, a late
coming interrupt may access structures that are not valid.
Improve timeout error handling by resetting variables, and changing
relevant logging.

Change-Id: Ie0ee2fd9c2ce1628c69e1975fe713a2a26d9e716
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>