Report traps and fatal exceptions through a wavefront's
amd_queue_t.queue_inactive_signal. Previously, only traps were
reported and requireed the compiler to pass in the signal pointer
in s[0:1].
The signal is obtained through a mapping from doorbell index to
amd_queue_t*. The doorbell is fetched within a wavefront through
the gfx9+ S_SENDMSG(MSG_GET_DOORBELL) instruction.
Change-Id: I319b45f2e15dfcfe4db8f4065da1136e9539a42b
Jay Cornwall
ff8f439112