libpfring: fix compilation warning

libpfring: fix compilation warning

Fix simple compilation warning with checking statically allocated
variables and missing fallthrough.
Fix compilation warning:
/home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c: In function 'ring_release':
/home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c:5489:6: error: the comparison will always evaluate as 'true' for the address of 'name' will never be NULL [-Werror=address]
 5489 |      && pfr->zc_device_entry->zc_dev.dev->name) {
      |      ^~
In file included from ./include/linux/rtnetlink.h:7,
                 from /home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c:84:
./include/linux/netdevice.h:1986:33: note: 'name' declared here
 1986 |         char                    name[IFNAMSIZ];
      |                                 ^~~~
/home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c: In function 'ring_bind':
/home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c:5620:18: error: the comparison will always evaluate as 'false' for the address of 'sa_data' will never be NULL [-Werror=address]
 5620 |   if(sa->sa_data == NULL)
      |                  ^~
In file included from /home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c:82:
./include/linux/socket.h:34:25: note: 'sa_data' declared here
   34 |         char            sa_data[14];    /* 14 bytes of protocol address */
      |                         ^~~~~~~
/home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c: In function 'hash_pkt_cluster':
/home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c:3937:7: error: this statement may fall through [-Werror=implicit-fallthrough=]
 3937 |     if(l3_proto == IPPROTO_TCP)
      |       ^
/home/ansuel/openwrt-ansuel/openwrt/build_dir/target-aarch64_cortex-a53_musl/linux-ipq807x_generic/PF_RING-8.0.0/kernel/pf_ring.c:3944:3: note: here
 3944 |   case cluster_per_flow_2_tuple:
      |   ^~~~
cc1: all warnings being treated as errors

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>