radv: Add ability to dump shaders based on stage.

The new debug flags can make the output less overwhelming
and only dump what we want to see.

The old RADV_DEBUG=shaders will still print all stages.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Konstantin Seurer <konstantin.seurer@gmail.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Acked-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32079>

docs/envvars.rst

@@ -1416,6 +1416,22 @@ RADV driver environment variables
       synchronize shaders after all draws/dispatches
    ``zerovram``
       initialize all memory allocated in VRAM as zero
+   ``vs``
+      Dump vertex shaders.
+   ``tcs``
+      Dump tessellation control shaders.
+   ``tes``
+      Dump tessellation evaluation shaders.
+   ``gs``
+      Dump geometry shaders.
+   ``ps``
+      Dump fragment shaders.
+   ``task``
+      Dump task shaders.
+   ``mesh``
+      Dump mesh shaders.
+   ``cs``
+      Dump compute (and ray tracing) shaders.
 
 .. envvar:: RADV_FORCE_FAMILY