Add option to disable ChromeOS

Those building Chromebook firmware from coreboot git might be more
interested in building without ChromeOS extras.

Change-Id: I2f176d059fd45bf4eb02cc0f3f1dcc353095d0ce
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3977
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/mainboard/intel/baskingridge/Kconfig

@@ -11,7 +11,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select HAVE_OPTION_TABLE
 	select HAVE_ACPI_RESUME
 	select HAVE_SMI_HANDLER
-	select CHROMEOS
+	select MAINBOARD_HAS_CHROMEOS
 	select LAPIC_MONOTONIC_TIMER
 
 config MAINBOARD_DIR