gallium: add PIPE_CAP_TGSI_MUL_ZERO_WINS

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Axel Davy <axel.davy@ens.fr>

src/gallium/docs/source/screen.rst

@@ -371,6 +371,8 @@ The integer capabilities:
   and lowering.
 * ``PIPE_CAP_TGSI_FS_FBFETCH``: Whether a fragment shader can use the FBFETCH
   opcode to retrieve the current value in the framebuffer.
+* ``PIPE_CAP_TGSI_MUL_ZERO_WINS``: Whether TGSI shaders support the
+  ``TGSI_PROPERTY_MUL_ZERO_WINS`` shader property.
 
 
 .. _pipe_capf: