phy: samsung: Merge Kconfig for Exynos5420 and Exynos5250

Exynos5420 variant of USB2 PHY is handled by the same code as the
Exynos5250 one. Introducing a separate Kconfig symbol for it was an
over-engineering, which turned out to cause build break for certain
configurations:

ERROR: modpost: "exynos5420_usb2_phy_config" [drivers/phy/samsung/phy-exynos-usb2.ko] undefined!

Fix this by removing PHY_EXYNOS5420_USB2 symbol and using
PHY_EXYNOS5250_USB2 also for Exynos5420 SoCs.

Reported-by: Markus Reichl <[e-mail]>
Fixes: 81b534f7e9b2 ("phy: samsung: Add support for the Exynos5420 variant of the USB2 PHY")
Signed-off-by: Marek Szyprowski <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Jaehoon Chung <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/phy/samsung/Kconfig

···
 config PHY_EXYNOS5250_USB2
 	bool
 	depends on PHY_SAMSUNG_USB2
-	default SOC_EXYNOS5250
-
-config PHY_EXYNOS5420_USB2
-	bool
-	depends on PHY_SAMSUNG_USB2
-	default SOC_EXYNOS5420
+	default SOC_EXYNOS5250 || SOC_EXYNOS5420
 
 config PHY_S5PV210_USB2
 	bool "Support for S5PV210"

drivers/phy/samsung/phy-samsung-usb2.c

···
 		.compatible = "samsung,exynos5250-usb2-phy",
 		.data = &exynos5250_usb2_phy_config,
 	},
-#endif
-#ifdef CONFIG_PHY_EXYNOS5420_USB2
 	{
 		.compatible = "samsung,exynos5420-usb2-phy",
 		.data = &exynos5420_usb2_phy_config,