usb.h: use standard __LITTLE_ENDIAN from Linux headers

Rather than forcing people to define a custom "LITTLEENDIAN", just use the
__LITTLE_ENDIAN one from the Linux byteorder headers that every arch is
already setting up.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Remy Bohmer <linux@bohmer.net>
diff --git a/cpu/arm920t/s3c24x0/usb_ohci.c b/cpu/arm920t/s3c24x0/usb_ohci.c
index 641f270..9cbd477 100644
--- a/cpu/arm920t/s3c24x0/usb_ohci.c
+++ b/cpu/arm920t/s3c24x0/usb_ohci.c
@@ -29,9 +29,7 @@
  */
 /*
  * IMPORTANT NOTES
- * 1 - you MUST define LITTLEENDIAN in the configuration file for the
- *     board or this driver will NOT work!
- * 2 - this driver is intended for use with USB Mass Storage Devices
+ * 1 - this driver is intended for use with USB Mass Storage Devices
  *     (BBB) ONLY. There is NO support for Interrupt or Isochronous pipes!
  */
 
diff --git a/cpu/mips/au1x00_usb_ohci.c b/cpu/mips/au1x00_usb_ohci.c
index 17489da..ea02efb 100644
--- a/cpu/mips/au1x00_usb_ohci.c
+++ b/cpu/mips/au1x00_usb_ohci.c
@@ -27,9 +27,7 @@
  */
 /*
  * IMPORTANT NOTES
- * 1 - you MUST define LITTLEENDIAN in the configuration file for the
- *     board or this driver will NOT work!
- * 2 - this driver is intended for use with USB Mass Storage Devices
+ * 1 - this driver is intended for use with USB Mass Storage Devices
  *     (BBB) ONLY. There is NO support for Interrupt or Isochronous pipes!
  */
 
@@ -56,7 +54,7 @@
 #define USBH_ENABLE_CE (1<<3)
 #define USBH_ENABLE_RD (1<<4)
 
-#ifdef LITTLEENDIAN
+#ifdef __LITTLE_ENDIAN
 #define USBH_ENABLE_INIT (USBH_ENABLE_CE | USBH_ENABLE_E | USBH_ENABLE_C)
 #else
 #define USBH_ENABLE_INIT (USBH_ENABLE_CE | USBH_ENABLE_E | USBH_ENABLE_C | USBH_ENABLE_BE)