phy: phy-brcm-usb: support PHY on the BCM4908

BCM4908 seems to have slightly different registers but works when
programmed just like the STB one.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210106205838.10964-3-zajec5@gmail.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/broadcom/Kconfig

@@ -91,10 +91,11 @@ config PHY_BRCM_SATA
 
 config PHY_BRCM_USB
 	tristate "Broadcom STB USB PHY driver"
-	depends on ARCH_BRCMSTB || COMPILE_TEST
+	depends on ARCH_BCM4908 || ARCH_BRCMSTB || COMPILE_TEST
 	depends on OF
 	select GENERIC_PHY
 	select SOC_BRCMSTB
+	default ARCH_BCM4908
 	default ARCH_BRCMSTB
 	help
 	  Enable this to support the Broadcom STB USB PHY.

drivers/phy/broadcom/phy-brcm-usb.c

@@ -286,6 +286,10 @@ static const struct match_chip_info chip_info_7445 = {
 };
 
 static const struct of_device_id brcm_usb_dt_ids[] = {
+	{
+		.compatible = "brcm,bcm4908-usb-phy",
+		.data = &chip_info_7445,
+	},
 	{
 		.compatible = "brcm,bcm7216-usb-phy",
 		.data = &chip_info_7216,