mesa: Remove cmd_size < 0 check.

cmd_size was changed to size_t in commit 4b244591 ("glthread: change sizes to unsigned or size_t where needed").

Fix defect reported by Coverity Scan.

Macro compares unsigned to 0 (NO_EFFECT) unsigned_compare: This less-than-zero comparison of an unsigned value is never true. cmd_size < 0UL

Signed-off-by: Vinson Lee vlee@freedesktop.org

cc: @mareko