intel: Rename genx keyword to gfxx in source files

Commands used to do the changes:
export SEARCH_PATH="src/intel src/gallium/drivers/iris src/mesa/drivers/dri/i965"
grep -E "gen[[:digit:]]+" -rIl $SEARCH_PATH | xargs sed -ie "s/gen\([[:digit:]]\+\)/gfx\1/g"

Exclude pack.h and xml changes in this patch:
grep -E "gfx[[:digit:]]+_pack\.h" -rIl $SEARCH_PATH | xargs sed -ie "s/gfx\([[:digit:]]\+_pack\.h\)/gen\1/g"
grep -E "gfx[[:digit:]]+\.xml" -rIl $SEARCH_PATH | xargs sed -ie "s/gfx\([[:digit:]]\+\.xml\)/gen\1/g"

Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9936>

src/intel/compiler/brw_eu_util.c

@@ -38,7 +38,7 @@ void brw_math_invert( struct brw_codegen *p,
 			     struct brw_reg dst,
 			     struct brw_reg src)
 {
-   gen4_math(p,
+   gfx4_math(p,
 	     dst,
 	     BRW_MATH_FUNCTION_INV,
 	     0,