meson: remove duplicate deprecated for gallium-xa option

Fixes: cf40099730 ("meson: deprecate gallium-xa")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34565>
(cherry picked from commit b9472db4963d3d434dc02a2adc7f6ce1e99ddaa1)

.pick_status.json

@@ -1504,7 +1504,7 @@
         "description": "meson: remove duplicate `deprecated` for `gallium-xa` option",
         "nominated": true,
         "nomination_type": 2,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "cf40099730c4af304227c30c891834cec220abff",
         "notes": null

meson.options

@@ -127,7 +127,6 @@ option(
 option(
   'gallium-xa',
   type : 'feature',
-  deprecated: {'true': 'enabled', 'false': 'disabled'},
   description : 'enable gallium xa frontend.',
   deprecated: true,
 )