msm: kgsl: Make OOB timeouts easier to debug

Instead of a vague message and a mask use actual string names and a nice
WARN() to make it easier for mere mortals to debug OOB timeouts.  Also
remove a unneeded global function and replace it with a smaller local
function.

Change-Id: Ic0dedbad470326854e8565d651d477cf54401f07
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>