staging: vchiq_arm: avoid crashing the kernel

Using BUG_ON in a non-essential driver isn't recommend. So better
trigger a stacktrace and bailout.

Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/1619347863-16080-2-git-send-email-stefan.wahren@i2se.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>