genxml: Silence unused parameter warnings in generated pack code

genxml: Silence unused parameter warnings in generated pack code

Reduces my build from 1960 warnings to 1808 warnings by silencing 152
instances of things like

In file included from ../../SOURCE/master/src/intel/genxml/genX_pack.h:32:0,
                 from ../../SOURCE/master/src/intel/isl/isl_emit_depth_stencil.c:36:
src/intel/genxml/gen4_pack.h: In function ‘__gen_uint’:
src/intel/genxml/gen4_pack.h:58:49: warning: unused parameter ‘end’ [-Wunused-parameter]
 __gen_uint(uint64_t v, uint32_t start, uint32_t end)
                                                 ^~~
src/intel/genxml/gen4_pack.h: In function ‘__gen_offset’:
src/intel/genxml/gen4_pack.h:94:35: warning: unused parameter ‘start’ [-Wunused-parameter]
 __gen_offset(uint64_t v, uint32_t start, uint32_t end)
                                   ^~~~~
src/intel/genxml/gen4_pack.h:94:51: warning: unused parameter ‘end’ [-Wunused-parameter]
 __gen_offset(uint64_t v, uint32_t start, uint32_t end)
                                                   ^~~
src/intel/genxml/gen4_pack.h: In function ‘__gen_ufixed’:
src/intel/genxml/gen4_pack.h:133:48: warning: unused parameter ‘end’ [-Wunused-parameter]
 __gen_ufixed(float v, uint32_t start, uint32_t end, uint32_t fract_bits)
                                                ^~~

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