msm: kgsl: Log the type of snapshot

Specify in the snapshot error log whether it's
a GMU only snapshot or a GPU snapshot. This helps
in quickly identifying what kind of snapshot is
being taken. Also, change the format of the log
to make it easier to pull snapshot from dumps.

Change-Id: I7f5765ac063e608a495d7e6331bbd55868fe120c
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>