cxgb3 - Stop mac RX when changing MTU

Rx traffic needs to be halted when the MTU is changed
to avoid a potential chip hang.
Reset/restore MAC filters around a MTU change.
Also fix the pause frames high materwark setting.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/cxgb3/regs.h b/drivers/net/cxgb3/regs.h
index bf9d6be..020859c 100644
--- a/drivers/net/cxgb3/regs.h
+++ b/drivers/net/cxgb3/regs.h
@@ -1882,6 +1882,10 @@
 #define V_COPYALLFRAMES(x) ((x) << S_COPYALLFRAMES)
 #define F_COPYALLFRAMES    V_COPYALLFRAMES(1U)
 
+#define S_DISBCAST    1
+#define V_DISBCAST(x) ((x) << S_DISBCAST)
+#define F_DISBCAST    V_DISBCAST(1U)
+
 #define A_XGM_RX_HASH_LOW 0x814
 
 #define A_XGM_RX_HASH_HIGH 0x818