mesa: Silence unused parameter warnings from TEXSTORE_PARAMS

mesa: Silence unused parameter warnings from TEXSTORE_PARAMS

Reduces my build from 1717 warnings to 1547 warnings by silencing 170
instances of things like

In file included from ../../SOURCE/master/src/mesa/main/texcompress_bptc.h:30:0,
                 from ../../SOURCE/master/src/mesa/main/texcompress_bptc.c:31:
../../SOURCE/master/src/mesa/main/texcompress_bptc.c: In function ‘_mesa_texstore_bptc_rgba_unorm’:
../../SOURCE/master/src/mesa/main/texstore.h:60:14: warning: unused parameter ‘dstFormat’ [-Wunused-parameter]
  mesa_format dstFormat, \
              ^
../../SOURCE/master/src/mesa/main/texcompress_bptc.c:1276:32: note: in expansion of macro ‘TEXSTORE_PARAMS’
 _mesa_texstore_bptc_rgba_unorm(TEXSTORE_PARAMS)
                                ^~~~~~~~~~~~~~~

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>