LEDE 17.01.7 & openvswitch 2.5.0: "struct inet_frags has no member named rnd" compile error

Release: 17.01.7
Target: ramips
Subtarget: rt305x
Model: D-Link DIR-620 A1
Package arch.: mipsel_24kc

When I try to build LEDE 17.01.7, I get errors when compiling openvswitch 2.5.0:

make[4]: Entering directory '/home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux'
make -C /home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/linux-4.4.182 M=/home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux modules
make[5]: Entering directory '/home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/linux-4.4.182'
  CC [M]  /home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux/nf_conntrack_reasm.o
In file included from include/linux/random.h:10:0,
                 from /home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux/compat/include/linux/random.h:4,
                 from include/linux/net.h:22,
                 from /home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux/compat/include/linux/net.h:4,
                 from /home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux/nf_conntrack_reasm.c:30:
/home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux/nf_conntrack_reasm.c: In function 'nf_hash_frag':
/home/17_01_7/build_dir/target-mipsel_24kc_musl-1.1.16/linux-ramips_rt305x/openvswitch-2.5.0/datapath/linux/nf_conntrack_reasm.c:80:31: error: 'struct inet_frags' has no member named 'rnd'
  net_get_random_once(&nf_frags.rnd, sizeof(nf_frags.rnd));

Previous release (17.01.6) compilation is successful (other things being equal).

For which rt305x device do you want to build OpenWrt 17.01?

What about using 19.07 or master instead?

D-Link DIR-620 A1
This device has only 32MB RAM, I tried to use 18.06.x and 19.07.x releases, but regularly got "out of memory" errors. Thus, 17.01 is optimal for this device with my configuration.

Yes, https://openwrt.org/toh/hwdata/d-link/d-link_dir-620_a1

This device is NOT RECOMMENDED for future use with OpenWrt due to low flash/ram.
1) This device does not have sufficient resources (flash and/or RAM) to provide secure and reliable operation.
This means that even setting a password or changing simple network settings might not be possible any more, rendering the device effectively useless. See OpenWrt on 4/32 devices what you can do now.

We should stop here, no use to further support this device. OpenWrt 17.01 is too old and has open security flaws. You need a newer device with more RAM to be able to run recent versions.

The same for TL-WR740N V4

There is no PATCH for this problem?