freedreno: a few misc patches
The last patch updates features.txt to check off a few extensions that we are already advertising..
I think we can also probably check off a few more sub-tasks on
ARB_gpu_shader5, and maybe some other things I overlooked. In st_extensions the only difference between ARB and EXT/OES of shader5 versions that we already advertise is the GLSL level (vs the ESSL feature level, but not sure the diff btwn GLSL 400 and ESSL 320 off the top of my head).