arch/x86: Select USB before selecting host driver

Kbuild complains if USB is not selected before any of host driver.

warning: (X86) selects USB_EHCI_HCD which has unmet direct dependencies (USB)
warning: (X86) selects USB_EHCI_HCD which has unmet direct dependencies (USB)

Select it for X86.

Fixes: 64d6ac5b ("Kconfig: USB: Migrate CONFIG_USB_EHCI_HCD users to Kconfig")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[bmeng: Update all x86 boards' defconfig files to remove CONFIG_USB]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>