hwdocs/pcounter: Update description of rop_samples_in_count
hwdocs/pcounter: Rename rop_pixels_killed_latez_count to rop_samples_killed_by_latez_count
hwdocs/pcounter: Rename rop_pixels_killed_earlyz_count to rop_samples_killed_by_earlyz_count
hwdocs/pcounter: Update description of RASTER signals according to the description from NVPerfKit
hwdocs/pcounter: s/b4/B4 and s/b6/B6
hwdocs/pcounter: Update TODO part of the RASTER signals
hwdocs/pcounter: Mark 408e50 as N/A for rop_waits_for_fb
hwdocs/pcounter: Update the RASTER signals table