USB: Standardize inclusion protection and add where missing.

For the header files in include/linux/usb, add missing multiple
inclusion protection and standardize what's already there.  The
apparent standards:

  * macro name of __LINUX_USB_headerfile_H
  * inclusion protection placed after leading comment block
  * macro name added as a comment on the final #endif
  * any obvious trivial whitespace cleanup associated with the above

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/usb/cdc.h b/include/linux/usb/cdc.h
index 94ee4ec..71e52f2 100644
--- a/include/linux/usb/cdc.h
+++ b/include/linux/usb/cdc.h
@@ -6,6 +6,9 @@
  * firmware based USB peripherals.
  */
 
+#ifndef __LINUX_USB_CDC_H
+#define __LINUX_USB_CDC_H
+
 #define USB_CDC_SUBCLASS_ACM			0x02
 #define USB_CDC_SUBCLASS_ETHERNET		0x06
 #define USB_CDC_SUBCLASS_WHCM			0x08
@@ -221,3 +224,4 @@
 	__le16	wLength;
 } __attribute__ ((packed));
 
+#endif /* __LINUX_USB_CDC_H */