usb: host: make USB_ARCH_HAS_?HCI obsolete

The three options USB_ARCH_HAS_{EHCI,OHCI,XHCI} are all well beyond
their recommended shelf life. They have caused numerous build failures
over the years because they are never completely correct, and with
the move to splitting out the platform specific back-ends out of the
driver, there is no real need for them any more. Also, the use of making
USB_ARCH_HAS_HCD depend on it is questionable since one can always enable
dummy_hc these days.

This patch enables them unconditionally for all platforms and
architectures, which means it is now possible to build host controller
drivers for machines that are known not to come with this hardware,
but that is just how we treat most other drivers.

In order to minimise the impact on existing architecture code and
defconfig files, all the Kconfig are left present for now. All platforms
that currently do 'select USB_ARCH_HAS_*' should subsequently be changed
not to select that. All drivers depending on USB_ARCH_HAS_HCD should
be changed to depend on USB_SUPPORT instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>