net: sfp: add support for HALNy GPON SFP

Add a quirk for the HALNy HL-GSFP module, which appears to have an
inverted RX_LOS signal, and maybe uses TX_FAULT as a serial port
transmit pin. Rather than use these hardware signals, switch to
using software polling for these status signals.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>