bonding: fix disabling of arp_interval and miimon

Currently if either arp_interval or miimon is disabled, they both get
disabled, and upon disabling they get executed once more which is not
the proper behaviour. Also when doing a no-op and disabling an already
disabled one, the other again gets disabled.
Also fix the error messages with the proper valid ranges, and a small
typo fix in the up delay error message (outputting "down delay", instead
of "up delay").

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>