gallium: add PIPE_CAP_BINDLESS_TEXTURE

Whether bindless texture operations are supported by the
underlying driver.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/gallium/drivers/softpipe/sp_screen.c

@@ -305,6 +305,7 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_CAN_BIND_CONST_BUFFER_AS_VERTEX:
    case PIPE_CAP_ALLOW_MAPPED_BUFFERS_DURING_EXECUTION:
    case PIPE_CAP_POST_DEPTH_COVERAGE:
+   case PIPE_CAP_BINDLESS_TEXTURE:
       return 0;
    case PIPE_CAP_SHADER_BUFFER_OFFSET_ALIGNMENT:
       return 4;