Avoid ambiguous vector casts.

Bug swiftshader:15

Change-Id: Ia42d21b4f2c9e19a839ffb414661f2dffa350692
Reviewed-on: https://swiftshader-review.googlesource.com/7711
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-on: https://swiftshader-review.googlesource.com/7630
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/Main/FrameBuffer.cpp b/src/Main/FrameBuffer.cpp
index 2ac2a49..d0add5e 100644
--- a/src/Main/FrameBuffer.cpp
+++ b/src/Main/FrameBuffer.cpp
@@ -621,7 +621,7 @@
 		{
 		case FORMAT_X8R8G8B8:
 		case FORMAT_A8R8G8B8:
-			*Pointer<UInt>(d) = UInt(As<Long>(Pack(As<UShort4>(c1), As<UShort4>(c1))));
+			*Pointer<Byte4>(d) = Byte4(Pack(As<UShort4>(c1), As<UShort4>(c1)));
 			break;
 		case FORMAT_X8B8G8R8:
 		case FORMAT_A8B8G8R8:
@@ -630,7 +630,7 @@
 			{
 				c1 = Swizzle(c1, 0xC6);
 
-				*Pointer<UInt>(d) = UInt(As<Long>(Pack(As<UShort4>(c1), As<UShort4>(c1))));
+				*Pointer<Byte4>(d) = Byte4(Pack(As<UShort4>(c1), As<UShort4>(c1)));
 			}
 			break;
 		case FORMAT_R8G8B8: