vgacon: fix mips/sibyte build regression

The conversion to vgacon_register_screen() was missing an #include statement
for the swarm board:

arch/mips/sibyte/swarm/setup.c:146:9: error: implicit declaration of function 'vgacon_register_screen' [-Werror=implicit-function-declaration]

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310240429.UqeQ2Cpr-lkp@intel.com/


Fixes: 555624c0 vgacon: clean up global screen_info instances
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20231024054412.2291220-1-arnd@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>