iptables: bump to 1.6.1

Switch to git repo
Removed musl patch
Refreshed existing patch

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [cleanup]

package/network/utils/iptables/patches/020-iptables-disable-modprobe.patch

@@ -1,6 +1,6 @@
 --- a/libxtables/xtables.c
 +++ b/libxtables/xtables.c
-@@ -336,6 +336,7 @@ static char *get_modprobe(void)
+@@ -355,6 +355,7 @@ static char *get_modprobe(void)
  
  int xtables_insmod(const char *modname, const char *modprobe, bool quiet)
  {
@@ -8,7 +8,7 @@
  	char *buf = NULL;
  	char *argv[4];
  	int status;
-@@ -380,6 +381,7 @@ int xtables_insmod(const char *modname, 
+@@ -395,6 +396,7 @@ int xtables_insmod(const char *modname,
  	free(buf);
  	if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
  		return 0;