netsniff-ng: nlmsg: Explicitly cast RTA_LEN to an int
It looks like the result of RTA_PAYLOAD() can be of different type
depending on architecture/kernel header version/...
In order to prevent warnings related to non-matching types, just
explicitly cast RTA_LEN to an int, since it can't possible be larger
than the unsigned short of rta_len anyhow and it is used as an in in the
call to device_addr2str().
Fixes:
664dcf4217 ("netsniff-ng: nlmsg: Use correct pritnf format specifier for int")
Reported-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>