msm: charm: Wait for status to go low in panic handler

When a panic occurs in the kernel, the external modem
responds and goes through its own shutdown process.
Wait until the external modem gives a signal that
it has finished shutting down (dropping MDM2AP_STATUS)
before exiting the panic handler.

CRs-Fixed: 303416
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
1 file changed