scsi: mac_esp: Avoid type warning from sparse

Avoid the following warning from "make C=1":

  CHECK   drivers/scsi/mac_esp.c
drivers/scsi/mac_esp.c:357:30: warning: incorrect type in initializer (different address spaces)
drivers/scsi/mac_esp.c:357:30:    expected unsigned char [usertype] *fifo
drivers/scsi/mac_esp.c:357:30:    got void [noderef] <asn:2>*
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mac_esp.c

@@ -348,7 +348,7 @@ static void mac_esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
 				 u32 dma_count, int write, u8 cmd)
 {
 	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
-	u8 *fifo = esp->regs + ESP_FDATA * 16;
+	u8 __iomem *fifo = esp->regs + ESP_FDATA * 16;
 
 	cmd &= ~ESP_CMD_DMA;
 	mep->error = 0;