x86: Introduce INTEL_MID quirk option

Intel Mobile Internet Device (MID) platforms have special treatment in
some cases, such as CPU enumeration or boot parameters configuration.

Besides that several drivers are specifically developed for the IP
blocks found on Intel MID platforms. Those drivers will be dependent to
this option.

Here we introduce specific quirk option for such cases.

It is supposed to be selected by Intel MID platform boards, for example,
Intel Edison.

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>