console: Change BOOTBLOCK_CONSOLE default to y

Invert the default instead of selecting it everywhere. Restores the
ability to use its Kconfig prompt.

Beside Qemu targets, the only platforms that didn't select it seem
to be samsung/exynos5420, intel/cannonlake, and intel/icelake. The
latter two were about to be patched anyway.

Change-Id: I7c5b671b7dddb5c6535c97c2cbb5f5053909dc64
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/30891
Reviewed-by: Lijian Zhao <lijian.zhao@intel.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/emulation/qemu-i440fx/Kconfig

@@ -12,7 +12,6 @@ config BOARD_SPECIFIC_OPTIONS
 	select BOARD_ROMSIZE_KB_256
 	select MAINBOARD_HAS_NATIVE_VGA_INIT
 	select MAINBOARD_FORCE_NATIVE_VGA_INIT
-	select BOOTBLOCK_CONSOLE
 	select NO_CAR_GLOBAL_MIGRATION
 
 config MAINBOARD_DIR