Fixing Linux build

There was an ambiguous type warning between Float4 and RValue<Float4>.

Change-Id: I526fc2430a66b8545e81fe5ae97fb423e7f01aec
Reviewed-on: https://swiftshader-review.googlesource.com/7356
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/Shader/VertexRoutine.cpp b/src/Shader/VertexRoutine.cpp
index 087e481..0d22162 100644
--- a/src/Shader/VertexRoutine.cpp
+++ b/src/Shader/VertexRoutine.cpp
@@ -603,7 +603,7 @@
 		if(stream.count < 1) v.x = Float4(0.0f);
 		if(stream.count < 2) v.y = Float4(0.0f);
 		if(stream.count < 3) v.z = Float4(0.0f);
-		if(stream.count < 4) v.w = isNativeFloatAttrib ? Float4(1.0f) : As<Float4>(Int4(0));
+		if(stream.count < 4) v.w = isNativeFloatAttrib ? As<Float4>(Float4(1.0f)) : As<Float4>(Int4(0));
 
 		return v;
 	}