net: sfp: add quirk for FS's 2.5G copper SFP

Add a quirk for a copper SFP that identifies itself as "FS" "SFP-2.5G-T".
This module's PHY is inaccessible, and can only run at 2500base-X with the
host without negotiation. Add a quirk to enable the 2500base-X interface mode
with 2500base-T support and disable auto negotiation.

Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microchip.com>
Link: https://lore.kernel.org/r/20230925080059.266240-1-Raju.Lakkaraju@microchip.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/phy/sfp.c

@@ -468,6 +468,9 @@ static const struct sfp_quirk sfp_quirks[] = {
 	SFP_QUIRK("HUAWEI", "MA5671A", sfp_quirk_2500basex,
 		  sfp_fixup_ignore_tx_fault),
 
+	// FS 2.5G Base-T
+	SFP_QUIRK_M("FS", "SFP-2.5G-T", sfp_quirk_oem_2_5g),
+
 	// Lantech 8330-262D-E can operate at 2500base-X, but incorrectly report
 	// 2500MBd NRZ in their EEPROM
 	SFP_QUIRK_M("Lantech", "8330-262D-E", sfp_quirk_2500basex),