lgc/patch: Cleanup useless (and misleading comments)
lgc/patch: Cleanup useless (and misleading comments)

Leave comments explaining (hopefully correct) rationales, but remove
comments that add nothing to the code. They were arguably hurting us
because they hid the overall structure (or lack of it) of the pass
pipeline.

GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc