Make DMA Fill macro actually work.

While most of the fill uses the upper byte, the second byte uses the
lower byte. I only noticed this because my emulator has to recreate
this quirk in order to pass Nemesis's VDP FIFO test ROM.

s2.macros.asm

@@ -35,7 +35,7 @@ dmaFillVRAM macro byte,addr,length
 	move.l	#(($9400|((((length)-1)&$FF00)>>8))<<16)|($9300|(((length)-1)&$FF)),(a5) ; DMA length ...
 	move.w	#$9780,(a5) ; VRAM fill
 	move.l	#$40000080|(((addr)&$3FFF)<<16)|(((addr)&$C000)>>14),(a5) ; Start at ...
-	move.w	#(byte)<<8,(VDP_data_port).l ; Fill with byte
+	move.w	#(byte)|((byte)<<8),(VDP_data_port).l ; Fill with byte
 .loop:	move.w	(a5),d1
 	btst	#1,d1
 	bne.s	.loop ; busy loop until the VDP is finished filling...