x86: kconfig: Move USB to platform Kconfig

Like other peripheral drivers, move USB related drivers to platform
Kconfig as well.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/quark/Kconfig b/arch/x86/cpu/quark/Kconfig
index 46dade3..ce0c454 100644
--- a/arch/x86/cpu/quark/Kconfig
+++ b/arch/x86/cpu/quark/Kconfig
@@ -19,6 +19,8 @@
 	imply MMC_SDHCI_SDMA
 	imply SPI_FLASH
 	imply SYS_NS16550
+	imply USB
+	imply USB_EHCI_HCD
 
 if INTEL_QUARK