If for a stage __CONSOLE_ENABLE__ is 0, then there would be no
prototype for a get_console_loglevel() definition.
Change-Id: I805078921a5cc1506685f8aada3af5c5241260b7
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50083
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>