sfp: add support for 1000Base-PX and 1000Base-BX10

Add support for decoding the transceiver information for 1000Base-PX and
1000Base-BX10.  These use 1000BASE-X protocol.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>