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>

arch/x86/Kconfig

@@ -80,6 +80,20 @@ config VENDOR_INTEL
 
 endchoice
 
+# subarchitectures-specific options below
+config INTEL_MID
+	bool "Intel MID platform support"
+	help
+	  Select to build a U-Boot capable of supporting Intel MID
+	  (Mobile Internet Device) platform systems which do not have
+	  the PCI legacy interfaces.
+
+	  If you are building for a PC class system say N here.
+
+	  Intel MID platforms are based on an Intel processor and
+	  chipset which consume less power than most of the x86
+	  derivatives.
+
 # board-specific options below
 source "board/advantech/Kconfig"
 source "board/congatec/Kconfig"