staging/solo6x10: depend on CONFIG_FONTS

The new SOLO6X10 driver needs the built-in console fonts, specifically
the VGA8x16 font and building it without console support results in
a link error error.

drivers/built-in.o: In function `solo_osd_print':
 :(.text+0x7d3424): undefined reference to `find_font'

This adds a dependency on the CONFIG_FONTS symbol and changes the
console code to always build the base driver even if there are
no specific fonts built-in.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>