netfilter: fix file clash during install of kmod-iptables

A regression in openwrt#21078 caused ip_tables.ko and x_tables.ko
to be installed by both kmod-nf-ipt and kmod-iptables:

 * check_data_file_clashes: Package kmod-nf-ipt wants to install file /Volumes/x64/openwrt/build_dir/target-x86_64_musl/root-x86/lib/modules/6.18.33/ip_tables.ko
	But that file is already provided by package  * kmod-iptables
 * check_data_file_clashes: Package kmod-nf-ipt wants to install file /Volumes/x64/openwrt/build_dir/target-x86_64_musl/root-x86/lib/modules/6.18.33/x_tables.ko

Remove the files from the install list of kmod-iptables, to avoid
errors during installation.

Fixes: openwrt#23630

Signed-off-by: Georgi Valkov <gvalkov@gmail.com>

Author: httpstorm

package/kernel/linux/modules/netfilter.mk

@@ -63,9 +63,7 @@ define KernelPackage/iptables
 	CONFIG_BRIDGE_NF_EBTABLES_LEGACY
   HIDDEN:=1
   DEPENDS:=@!LINUX_6_12
-  FILES:= \
-	$(LINUX_DIR)/net/ipv4/netfilter/ip_tables.ko \
-	$(LINUX_DIR)/net/netfilter/x_tables.ko
+  FILES:=
   AUTOLOAD:=$(call AutoProbe,$(notdir ip_tables x_tables))
 endef