powerpc/8xxx: Cleanup USB device-tree fixup

Some code cleanup done for USB device-tree fixup:
	- handling error value returned from fdt_fixup_usb_mode_phy_type()
	- using ARRAY_SIZE macro
	- using snprintf instead of sprintf

Signed-off-by: Ramneek Mehresh <ramneek.mehresh@freescale.com>

arch/powerpc/cpu/mpc8xxx/fdt.c

 /*
- * Copyright 2009-2011 Freescale Semiconductor, Inc.
+ * Copyright 2009-2012 Freescale Semiconductor, Inc.
  *
  * This file is derived from arch/powerpc/cpu/mpc85xx/cpu.c and
  * arch/powerpc/cpu/mpc86xx/cpu.c. Basically this file contains
@@ -137,28 +137,34 @@ void fdt_fixup_dr_usb(void *blob, bd_t *bd)
 
 	for (i = 1; i <= FSL_MAX_NUM_USB_CTRLS; i++) {
 		int mode_idx = -1, phy_idx = -1;
-		sprintf(str, "%s%d", "usb", i);
+		snprintf(str, 5, "%s%d", "usb", i);
 		if (hwconfig(str)) {
-			for (j = 0; j < sizeof(modes); j++) {
+			for (j = 0; j < ARRAY_SIZE(modes); j++) {
 				if (hwconfig_subarg_cmp(str, "dr_mode",
 						modes[j])) {
 					mode_idx = j;
 					break;
 				}
 			}
-			for (j = 0; j < sizeof(phys); j++) {
+			for (j = 0; j < ARRAY_SIZE(phys); j++) {
 				if (hwconfig_subarg_cmp(str, "phy_type",
 						phys[j])) {
 					phy_idx = j;
 					break;
 				}
 			}
-			if (mode_idx >= 0)
+			if (mode_idx >= 0) {
 				usb_mode_off = fdt_fixup_usb_mode_phy_type(blob,
 					modes[mode_idx], NULL, usb_mode_off);
-			if (phy_idx >= 0)
+				if (usb_mode_off < 0)
+					return;
+			}
+			if (phy_idx >= 0) {
 				usb_phy_off = fdt_fixup_usb_mode_phy_type(blob,
 					NULL, phys[phy_idx], usb_phy_off);
+				if (usb_phy_off < 0)
+					return;
+			}
 			if (!strcmp(str, "usb1"))
 				usb1_defined = 1;
 			if (mode_idx < 0 && phy_idx < 0)