cxgb3 - Update rx coalescing length

Reduce Rx coalescing length to 12288
Large bursts from the adapter to the host create back pressure
on the chip. Reducing the burst size avoids the issue.
Signed-off-by: NDivy Le Ray <divy@chelsio.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

drivers/net/cxgb3/common.h

@@ -104,7 +104,7 @@ enum {
 	PROTO_SRAM_LINES = 128, /* size of TP sram */
 };
 
-#define MAX_RX_COALESCING_LEN 16224U
+#define MAX_RX_COALESCING_LEN 12288U
 
 enum {
 	PAUSE_RX = 1 << 0,