This patch splits memconsole.c in 2 parts. One containing the
architecture-independent part and the other one containing the EBDA
specific part. This prepares the integration of coreboot support for the
memconsole.

The memconsole driver is now named as memconsole-x86-legacy.
Signed-off-by: NThierry Escande <thierry.escande@collabora.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>