r8169: remove unused variable

all references got removed by 865c652d
(r8169: remove non-napi code).
Signed-off-by: NFlorian Westphal <fwestphal@astaro.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/r8169.c

@@ -51,9 +51,6 @@
 #define TX_BUFFS_AVAIL(tp) \
 	(tp->dirty_tx + NUM_TX_DESC - tp->cur_tx - 1)
 
-/* Maximum events (Rx packets, etc.) to handle at each interrupt. */
-static const int max_interrupt_work = 20;
-
 /* Maximum number of multicast addresses to filter (vs. Rx-all-multicast).
    The RTL chips use a 64 element hash table based on the Ethernet CRC. */
 static const int multicast_filter_limit = 32;