usb: Remove references to non-existent PLAT_S5P symbol

The PLAT_S5P Kconfig symbol was removed in commit d78c16c
("ARM: SAMSUNG: Remove remaining legacy code"). There are still
some references left, fix that by replacing them with ARCH_S5PV210.

Fixes: d78c16c ("ARM: SAMSUNG: Remove remaining legacy code")
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/Kconfig

@@ -234,7 +234,7 @@ config USB_EHCI_SH
 
 config USB_EHCI_EXYNOS
        tristate "EHCI support for Samsung S5P/EXYNOS SoC Series"
-       depends on PLAT_S5P || ARCH_EXYNOS
+       depends on ARCH_S5PV210 || ARCH_EXYNOS
        help
 	Enable support for the Samsung Exynos SOC's on-chip EHCI controller.
 
@@ -550,7 +550,7 @@ config USB_OHCI_SH
 
 config USB_OHCI_EXYNOS
 	tristate "OHCI support for Samsung S5P/EXYNOS SoC Series"
-	depends on PLAT_S5P || ARCH_EXYNOS
+	depends on ARCH_S5PV210 || ARCH_EXYNOS
 	help
 	 Enable support for the Samsung Exynos SOC's on-chip OHCI controller.