net: phy: realtek: add support for RTL8126A-integrated 5Gbps PHY

A user reported that first consumer mainboards show up with a RTL8126A
5Gbps MAC/PHY. This adds support for the integrated PHY, which is also
available stand-alone. From a PHY driver perspective it's treated the
same as the 2.5Gbps PHY's, we just have to support the new PHY ID.
Reported-by: Joe Salmeri <jmscdba@gmail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Joe Salmeri <jmscdba@gmail.com>
Link: https://lore.kernel.org/r/0c8e67ea-6505-43d1-bd51-94e7ecd6e222@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/realtek.c

@@ -1047,6 +1047,16 @@ static struct phy_driver realtek_drvs[] = {
 		.resume         = rtlgen_resume,
 		.read_page      = rtl821x_read_page,
 		.write_page     = rtl821x_write_page,
+	}, {
+		PHY_ID_MATCH_EXACT(0x001cc862),
+		.name           = "RTL8251B 5Gbps PHY",
+		.get_features   = rtl822x_get_features,
+		.config_aneg    = rtl822x_config_aneg,
+		.read_status    = rtl822x_read_status,
+		.suspend        = genphy_suspend,
+		.resume         = rtlgen_resume,
+		.read_page      = rtl821x_read_page,
+		.write_page     = rtl821x_write_page,
 	}, {
 		PHY_ID_MATCH_EXACT(0x001cc961),
 		.name		= "RTL8366RB Gigabit Ethernet",