ice: Suppress false-positive style issues reported by static analyzer

A recent version of cppcheck falsely reports-
Variable ip.hdr is assigned a value that is never used.

ip is a union so the pointer ip.hdr is actually used when referenced as
ip.v4 and ip.v6. Silence these false reports when using cppcheck with the
--inline-suppr command-line option.

Signed-off-by: Bruce Allan <[e-mail]>
Signed-off-by: Anirudh Venkataramanan <[e-mail]>
Tested-by: Andrew Bowers <[e-mail]>
Signed-off-by: Jeff Kirsher <[e-mail]>

drivers/net/ethernet/intel/ice/ice_txrx.c

···
 	if (err < 0)
 		return err;
 
+	/* cppcheck-suppress unreadVariable */
 	ip.hdr = skb_network_header(skb);
 	l4.hdr = skb_transport_header(skb);