net: netlink: rename NETLINK_DUMP_STRICT_CHK -> NETLINK_GET_STRICT_CHK

NETLINK_DUMP_STRICT_CHK can be used for all GET requests,
dumps as well as doit handlers.  Replace the DUMP in the
name with GET make that clearer.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>