ip_gre: clean up some inconsistent indenting

No functional modification involved.

net/ipv4/ip_gre.c:192 ipgre_err() warn: inconsistent indenting.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=5375
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_gre.c

@@ -189,10 +189,10 @@ static int ipgre_err(struct sk_buff *skb, u32 info,
 	}
 
 #if IS_ENABLED(CONFIG_IPV6)
-       if (tpi->proto == htons(ETH_P_IPV6) &&
-           !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len,
-				       type, data_len))
-               return 0;
+	if (tpi->proto == htons(ETH_P_IPV6) &&
+	    !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len,
+					type, data_len))
+		return 0;
 #endif
 
 	if (t->parms.iph.daddr == 0 ||