tokenring: delete last holdout of CONFIG_TR

Tokenring support was deleted in v3.5. One last holdout of the macro
CONFIG_TR escaped that fate. Until now.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -144,8 +144,6 @@ static inline bool dev_xmit_complete(int rc)
 # else
 #  define LL_MAX_HEADER 96
 # endif
-#elif IS_ENABLED(CONFIG_TR)
-# define LL_MAX_HEADER 48
 #else
 # define LL_MAX_HEADER 32
 #endif