net: microchip: vcap api: Use ERR_CAST() in vcap_decode_rule()

There is a warning reported by coccinelle:

./drivers/net/ethernet/microchip/vcap/vcap_api.c:2399:9-16: WARNING:
ERR_CAST can be used with ri

Use ERR_CAST instead of ERR_PTR + PTR_ERR to simplify the
conversion process.
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/vcap/vcap_api.c

@@ -2396,7 +2396,7 @@ struct vcap_rule *vcap_decode_rule(struct vcap_rule_internal *elem)
 
 	ri = vcap_dup_rule(elem, elem->state == VCAP_RS_DISABLED);
 	if (IS_ERR(ri))
-		return ERR_PTR(PTR_ERR(ri));
+		return ERR_CAST(ri);
 
 	if (ri->state == VCAP_RS_DISABLED)
 		goto out;