um: Avoid pcap multiple definition errors

Change the function name in pcap_kern to avoid conflicting with
libpcap.a.

e.g.
ld: /usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../lib64/libpcap.a(pcap.o): in function `pcap_init':
(.text+0x7f0): multiple definition of `pcap_init'; arch/um/drivers/pcap_kern.o:pcap_kern.c:(.text.unlikely+0x0): first defined here
Signed-off-by: Peter Foley <pefoley2@pefoley.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/drivers/pcap_kern.c

@@ -15,7 +15,7 @@ struct pcap_init {
 	char *filter;
 };
 
-void pcap_init(struct net_device *dev, void *data)
+void pcap_init_kern(struct net_device *dev, void *data)
 {
 	struct uml_net_private *pri;
 	struct pcap_data *ppri;
@@ -44,7 +44,7 @@ static int pcap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
 }
 
 static const struct net_kern_info pcap_kern_info = {
-	.init			= pcap_init,
+	.init			= pcap_init_kern,
 	.protocol		= eth_protocol,
 	.read			= pcap_read,
 	.write			= pcap_write,