mesh: Fix address overrun error in rx filter

mesh: Fix address overrun error in rx filter

This fixes the following error for invalid read access when registering
filter for incoming messages:

140632==ERROR: AddressSanitizer: stack-buffer-overflow on address...
 #0 0x7f60c185741d in MemcmpInterceptorCommon(...
    #1 0x7f60c1857af8 in __interceptor_memcmp (/lib64/libasan.so...
    #2 0x55a10101536e in find_by_filter mesh/mesh-io-unit.c:494
    #3 0x55a1010d8c46 in l_queue_remove_if ell/queue.c:517
    #4 0x55a101014ebd in recv_register mesh/mesh-io-unit.c:506
    #5 0x55a10102946f in mesh_net_attach mesh/net.c:2885
    #6 0x55a101086f64 in send_reply mesh/dbus.c:153
    #7 0x55a101124c3d in handle_method_return ell/dbus.c:216
    #8 0x55a10112c8ef in message_read_handler ell/dbus.c:276
    #9 0x55a1010dae20 in io_callback ell/io.c:120
    #10 0x55a1010dff7e in l_main_iterate ell/main.c:478
    #11 0x55a1010e06e3 in l_main_run ell/main.c:525
    #12 0x55a1010e06e3 in l_main_run ell/main.c:507
    #13 0x55a1010e0bfc in l_main_run_with_signal ell/main.c:647
    #14 0x55a10100316e in main mesh/main.c:292
    #15 0x7f60c0c6855f in __libc_start_call_main (/lib64/libc.so.6+...
    #16 0x7f60c0c6860b in __libc_start_main_alias_1 (/lib64/libc.so.6+...
    #17 0x55a101003ce4 in _start (/home/istotlan/bluez/mesh/bluetooth-m...

Signed-off-by: Manika Shrivastava <manika.sh@samsung.com>
Signed-off-by: Ayush Garg <ayush.garg@samsung.com>