net/handshake: Fix section mismatch in handshake_exit

If CONFIG_NET_NS=n (e.g. m68k/defconfig):

    WARNING: modpost: vmlinux.o: section mismatch in reference: handshake_exit (section: .exit.text) -> handshake_genl_net_ops (section: .init.data)
    ERROR: modpost: Section mismatches detected.

Fix this by dropping the __net_initdata tag from handshake_genl_net_ops.

Fixes: 3b3009ea ("net/handshake: Create a NETLINK service for handling handshake requests")
Reported-by:  <noreply@ellerman.id.au>
Closes: http://kisskb.ellerman.id.au/kisskb/buildresult/14912987


Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20230420173723.3773434-1-geert@linux-m68k.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>