msm: kgsl: Properly deal with global pagetable mapping failures

Error if one of the global pagetables fails to map properly. Do not
continue onto the next pagetable which could map successfully and
mask that we had a failure.

Change-Id: I4dac0909e257a14c9d13c4698df3b67d96aa98e8
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>