rocker: Simplify the calculation of variables

Fix the following coccicheck warnings:

./drivers/net/ethernet/rocker/rocker_ofdpa.c:926:34-36: WARNING !A || A
&& B is equivalent to !A || B.

Reported-by: Abaci Robot <[e-mail]>
Signed-off-by: Jiapeng Zhong <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/rocker/rocker_ofdpa.c

···
 	struct ofdpa_flow_tbl_entry *entry;
 	u32 priority;
 	bool vlan_bridging = !!vlan_id;
-	bool dflt = !eth_dst || (eth_dst && eth_dst_mask);
+	bool dflt = !eth_dst || eth_dst_mask;
 	bool wild = false;
 
 	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);