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/soc/sifive/fu540/Kconfig

@@ -18,7 +18,6 @@ config SOC_SIFIVE_FU540
 	select ARCH_VERSTAGE_RISCV
 	select ARCH_ROMSTAGE_RISCV
 	select ARCH_RAMSTAGE_RISCV
-	select BOOTBLOCK_CONSOLE
 	select DRIVERS_UART_SIFIVE
 	select GENERIC_UDELAY
 	select HAVE_MONOTONIC_TIMER