[Freedreno] Cleanup of -Wunused-const-variable in drivers/gpu/drm/msm/disp/dpu1/dpu_formats.c

[Nathan Huckleberry]

Hey all,

I'm looking into cleaning up ignored warnings in the kernel so we can
remove compiler flags to ignore warnings.

There are several unused variables in dpu_formats.c
('dpu_format_map_tile', 'dpu_format_map_p010',
'dpu_format_map_p010_ubwc', 'dpu_format_map_tp10_ubwc').
They look like modifiers that were never implemented. I'd like to
remove these variables if there are no plans moving forward to
implement them. Otherwise I'll just leave them.

https://github.com/ClangBuiltLinux/linux/issues/528

Thanks,
Nathan Huckleberry