x86, mrst: remove Moorestown specific serial drivers

Intel Moorestown platform support was removed few years ago. This is a follow
up which removes Moorestown specific code for the serial devices. It includes
mrst_max3110 and earlyprintk bits.

This was used on SFI (Medfield, Clovertrail) based platforms as well, though
new ones use normal serial interface for the console service.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>