msm: kgsl: Fix a missing semicolon in the KGSL IOMMU handler

in check_if_freed() a call to kgsl_get_memory_usage() was terminated with
a comma instead of a semicolon.  Through a quirk in a macro this somehow
managed to compile and function properly but that doesn't make it okay.

CRs-fixed: 497280
Change-Id: Ic0dedbadfdf901bbc68b7f8cefb231d08dd01a95
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>