serial: 8250_mid: Enable HSU on Intel Cedar Fork PCH

Intel Cedar Fork PCH has similar HSU as has been used on Intel Denverton.
Add PCI ID to get it enumerated.

While here, remove DNV part form INTEL_MID_UART_DNV_FISR to show that is
used not only on Intel Denverton from now on.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>