net: phy: sfp: correct store of detected link modes

The link modes that sfp_parse_support() detects are stored in the
'modes' bitmap. There is no reason to make an exception for 1000Base-PX
or 1000Base-BX10.

Fixes: 03145864 ("sfp: support 1G BiDi (eg, FiberStore SFP-GE-BX) modules")
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>