freedreno/ir3: treat clipvertex like a normal varying

We need this in case it is streamed out.  Not sure why we were treating
it specially before.  Having it as a VS out is harmless if FS doesn't
have a matching input.

Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
index bfc04a7..b0f40f1 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
@@ -2151,10 +2151,8 @@
 		case VARYING_SLOT_FOGC:
 		case VARYING_SLOT_CLIP_DIST0:
 		case VARYING_SLOT_CLIP_DIST1:
-			break;
 		case VARYING_SLOT_CLIP_VERTEX:
-			/* handled entirely in nir_lower_clip: */
-			return;
+			break;
 		default:
 			if (slot >= VARYING_SLOT_VAR0)
 				break;