net: sfp: relax bitrate-derived mode check

Do not check the encoding when deriving 1000BASE-X from the bitrate
when no other modes are discovered. Some GPON modules (VSOL V2801F
and CarlitoxxPro CPGOS03-0490 v2.0) indicate NRZ encoding with a
1200Mbaud bitrate, but should be driven with 1000BASE-X on the host
side.
Tested-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/sfp-bus.c

@@ -334,14 +334,13 @@ void sfp_parse_support(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
 	}
 
 	/* If we haven't discovered any modes that this module supports, try
-	 * the encoding and bitrate to determine supported modes. Some BiDi
-	 * modules (eg, 1310nm/1550nm) are not 1000BASE-BX compliant due to
-	 * the differing wavelengths, so do not set any transceiver bits.
+	 * the bitrate to determine supported modes. Some BiDi modules (eg,
+	 * 1310nm/1550nm) are not 1000BASE-BX compliant due to the differing
+	 * wavelengths, so do not set any transceiver bits.
 	 */
 	if (bitmap_empty(modes, __ETHTOOL_LINK_MODE_MASK_NBITS)) {
-		/* If the encoding and bit rate allows 1000baseX */
-		if (id->base.encoding == SFF8024_ENCODING_8B10B && br_nom &&
-		    br_min <= 1300 && br_max >= 1200)
+		/* If the bit rate allows 1000baseX */
+		if (br_nom && br_min <= 1300 && br_max >= 1200)
 			phylink_set(modes, 1000baseX_Full);
 	}