video: sh_mobile_lcdcfb depends on meram

The sh_mobile_lcdcfb driver calls interfaces provided
by the corresponding "meram" helper. This fails if meram
is a module but lcdcfb is built-in.

To work around it, this uses special Kconfig magic to
only allow lcdcfb to be built if
a) both are modules,
b) meram is built-in, or
c) meram is disabled and the helpers stubbed out

Changing meram from 'y' to 'm' now forces clcd to
be a module as well, which seems to be the desired
behavior.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: linux-sh@vger.kernel.org
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>