msm: kgsl: Ignore kgsl flags while submitting cmds

Allow KGSL_CMD_FLAGS_EOF(end of frame) marker flag to
pass while adding userspace commands to ringbuffer.

CRs-fixed: 564030

Change-Id: I730143d2d1a0f3231705371f2119c55e277849e2
Signed-off-by: Anshuman Dani <adani@codeaurora.org>