net/ncsi: Fixup .dumpit message flags and ID check in Netlink handler

The ncsi_pkg_info_all_nl() .dumpit handler is missing the NLM_F_MULTI
flag, causing additional package information after the first to be lost.
Also fixup a sanity check in ncsi_write_package_info() to reject out of
range package IDs.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>