radeonsi: bump glsl version to 450 for nir backend

We still have more work to do but piglit results are looking
pretty good.

At GLSL 1.50 we have 30647/31118 piglit tests passing.
At GLSL 4.50 we have 37927/38551 piglit tests passing.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/gallium/drivers/radeonsi/si_get.c

@@ -226,8 +226,6 @@ static int si_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 		return 4;
 
 	case PIPE_CAP_GLSL_FEATURE_LEVEL:
-		if (sscreen->debug_flags & DBG(NIR))
-			return 150; /* no tessellation shaders yet */
 		if (si_have_tgsi_compute(sscreen))
 			return 450;
 		return 420;
@@ -451,10 +449,7 @@ static int si_get_shader_param(struct pipe_screen* pscreen,
 	case PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT:
 		return 32;
 	case PIPE_SHADER_CAP_PREFERRED_IR:
-		if (sscreen->debug_flags & DBG(NIR) &&
-		    (shader == PIPE_SHADER_VERTEX ||
-		     shader == PIPE_SHADER_GEOMETRY ||
-		     shader == PIPE_SHADER_FRAGMENT))
+		if (sscreen->debug_flags & DBG(NIR))
 			return PIPE_SHADER_IR_NIR;
 		return PIPE_SHADER_IR_TGSI;
 	case PIPE_SHADER_CAP_LOWER_IF_THRESHOLD: