msm: kgsl: Fixup kernel API changes

Life goes on, and so does the kernel. Update some API changes since
msm-4.19 including helper functions for vmfault functions, renaming
a memory statistic, updating cmd-db and removing __mutex_user which
is not longer available.

Change-Id: Ic0dedbad0b24042f3683a4be99888a0aa86baf78
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>