gallium/swr: Remove common code and build options

This commit removes all OpenSWR references from common Mesa code
and build system.

Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11264>

meson_options.txt

@@ -75,7 +75,7 @@ option(
   choices : [
     'auto', 'kmsro', 'radeonsi', 'r300', 'r600', 'nouveau', 'freedreno',
     'swrast', 'v3d', 'vc4', 'etnaviv', 'tegra', 'i915', 'svga', 'virgl',
-    'swr', 'panfrost', 'iris', 'lima', 'zink', 'd3d12', 'asahi', 'crocus'
+    'panfrost', 'iris', 'lima', 'zink', 'd3d12', 'asahi', 'crocus'
   ],
   description : 'List of gallium drivers to build. If this is set to auto all drivers applicable to the target OS/architecture will be built'
 )
@@ -412,19 +412,6 @@ option(
   choices : ['8', '16', '32'],
   description : 'Number of channel bits for OSMesa.'
 )
-option(
-  'swr-arches',
-  type : 'array',
-  value : ['avx', 'avx2'],
-  choices : ['avx', 'avx2', 'knl', 'skx'],
-  description : 'Architectures to build SWR support for.',
-)
-option(
-  'shared-swr',
-  type : 'boolean',
-  value : true,
-  description : 'Whether to link SWR shared or statically.',
-)
 
 option(
   'tools',