net: usb: lan78xx: annotate checksum assignment to silence sparse warnings

sparse warns about suspicious type casts in checksum assignment:

drivers/net/usb/lan78xx.c:3865:29: warning: cast to restricted __be16
drivers/net/usb/lan78xx.c:3865:27: warning: incorrect type in assignment
    (different base types) expected restricted __wsum [usertype] csum
got unsigned short [usertype]

Use __force to annotate the casts from u16 to __be16 to __wsum.
This makes the type conversion explicit and silences the warnings.
The code is otherwise correct; this change only clarifies intent.

Signed-off-by: Oleksij Rempel <[email protected]>
Signed-off-by: NipaLocal <nipa@local>

Author: olerem

drivers/net/usb/lan78xx.c

@@ -3819,7 +3819,10 @@ static void lan78xx_rx_csum_offload(struct lan78xx_net *dev,
 	     !(dev->net->features & NETIF_F_HW_VLAN_CTAG_RX))) {
 		skb->ip_summed = CHECKSUM_NONE;
 	} else {
-		skb->csum = ntohs((u16)(rx_cmd_b >> RX_CMD_B_CSUM_SHIFT_));
+		__be16 csum_raw;
+
+		csum_raw = (__force __be16)(rx_cmd_b >> RX_CMD_B_CSUM_SHIFT_);
+		skb->csum = (__force __wsum)ntohs(csum_raw);
 		skb->ip_summed = CHECKSUM_COMPLETE;
 	}
 }