msm: kgsl: Ensure signals do not cause waits to end early

Move to using uninterruptible (which will bail if any signal is received)
when waiting on events.  A signal was causing the wait to finish
prematurely, freeing memory while the GPU was still using it.  This caused
quite a few page faults and the device to become unstable.

Change-Id: Ic0dedbade9143c9377830a209c3ffd252aa9668b
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
msm: kgsl: Panic if global timestamp wait fails in context detach

If we timeout while waiting for the last issued global timestamp for
a detaching context to expire (10 seconds!) then we are on a fast
train to crashville.  BUG_ON() so we can stand a chance of debugging
this very rare issue.

Change-Id: Ic0dedbaddb9cbc5681f9c872785ce26b7cf9b87b
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>