soc: qcom: glink: Panic if RPM does not respond to SSR notification

If RPM does not respond to an SSR notification, the whole SoC must be
restarted, as RPM itself cannot be restarted. However, the G-Link SSR
driver silently fails in this case.

Modify the G-Link SSR driver to cause a kernel panic if RPM does not
respond to an SSR notification.

Change-Id: I2852d3e08c58c2c2f661da0c42b77b6e037abf1f
Signed-off-by: Steven Cahail <scahail@codeaurora.org>