msm: kgsl: Don't try to wait for fences that have been signaled

Trying to wait for fences that have already been signaled incurs a high
setup cost, since dynamic memory allocation must be used. Avoiding this
overhead when it isn't needed improves performance.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
Signed-off-by: Danny Lin <danny@kdrag0n.dev>