msm: kgsl: Allocate space in ringbuffer for EOF commands

When userspace passes end of frame (EOF) flag, ringbuffer is
inserted with EOF marker commands. Allocate ringbuffer space
for EOF marker commands.

CRs-Fixed: 469807
Change-Id: I7de8d1b81d358a8d8753ac84fbdceddad27bb17d
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>