msm: kgsl: remove redundant check for usermem type

The check for usermem type, while updating the stat
for memory mapped to userspace is not required.
Memory with usermem type KGSL_MEM_ENTRY_ION is not
mapped to user by kgsl and the mapsize would always be
zero. So remove the unnecessary check for usermem type.

Change-Id: Iaa0b86d1c7160657de1d802f2cc10c3bdbdf84b3
Signed-off-by: Puranam V G Tejaswi <pvgtejas@codeaurora.org>