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_compile_sf.c

@@ -345,7 +345,7 @@ static void invert_det( struct brw_sf_compile *c)
    /* Looks like we invert all 8 elements just to get 1/det in
     * position 2 !?!
     */
-   gen4_math(&c->func,
+   gfx4_math(&c->func,
 	     c->inv_det,
 	     BRW_MATH_FUNCTION_INV,
 	     0,
@@ -633,7 +633,7 @@ static void brw_emit_point_sprite_setup(struct brw_sf_compile *c, bool allocate)
       if (pc_coord_replace) {
 	 set_predicate_control_flag_value(p, c, pc_coord_replace);
 	 /* Caculate 1.0/PointWidth */
-	 gen4_math(&c->func,
+	 gfx4_math(&c->func,
 		   c->tmp,
 		   BRW_MATH_FUNCTION_INV,
 		   0,