ethtool: fix oops in ethtool_set_pauseparam()

The function pointers which were checked were for their get_* counterparts.
Typically a copy-paste typo.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Acked-by: Jeff Garzik <jeff@garzik.org>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>