GCC4.6: Squash warnings in ahci.c

ahci.c: In function 'ahci_port_start':
ahci.c:401: warning: format '%x' expects type 'unsigned int', but argument 2 has
type 'struct ahci_cmd_hdr *'

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Mike Frysinger <vapier@gentoo.org>

drivers/block/ahci.c

@@ -398,7 +398,7 @@ static int ahci_port_start(u8 port)
 	 * 32 bytes each in size
 	 */
 	pp->cmd_slot = (struct ahci_cmd_hdr *)mem;
-	debug("cmd_slot = 0x%x\n", pp->cmd_slot);
+	debug("cmd_slot = %p\n", pp->cmd_slot);
 	mem += (AHCI_CMD_SLOT_SZ + 224);
 
 	/*