platform/x86: intel_scu_ipc: Remove Lincroft support

Moorestown support was removed years ago with by the commit 1a8359e4
("x86/mid: Remove Intel Moorestown"). Lincroft is the CPU side chip of
Moorestown and not supported anymore so remove the code from the driver.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>