Staging: brcm80211: typedefs.h: remove NULL definition

No need for a driver to define NULL, the core kernel handles that.

Cc: Brett Rudley <brudley@broadcom.com>
Cc: Henry Ptasinski <henryp@broadcom.com>
Cc: Nohee Ko <noheek@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/brcm80211/include/typedefs.h b/drivers/staging/brcm80211/include/typedefs.h
index 10cb839..6e43f88 100644
--- a/drivers/staging/brcm80211/include/typedefs.h
+++ b/drivers/staging/brcm80211/include/typedefs.h
@@ -96,10 +96,6 @@
 #define TRUE	1		/* TRUE */
 #endif
 
-#ifndef NULL
-#define	NULL	0
-#endif
-
 #ifndef OFF
 #define	OFF	0
 #endif