staging: rtl8188eu: remove DBG_88E_LEVEL macro from include/rtw_debug.h

Remove definition of DBG_88E_LEVEL macro from include/rtw_debug.h, as it
no longer has any callers and does not follow kernel coding conventions.
Removing all such macros will ultimately allow the removal of this file.
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210623234902.7411-7-phil@philpotter.co.ukSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/include/rtw_debug.h

@@ -58,12 +58,6 @@
 
 extern u32 GlobalDebugLevel;
 
-#define DBG_88E_LEVEL(_level, fmt, arg...)				\
-	do {								\
-		if (_level <= GlobalDebugLevel)				\
-			pr_info(DRIVER_PREFIX fmt, ##arg);	\
-	} while (0)
-
 #define MSG_88E(...)							\
 	do {								\
 		if (_drv_err_ <= GlobalDebugLevel)			\