console/dummy: leave .con_font_get set to NULL

When this method is set, the caller expects struct console_font fields
to be properly initialized when it returns. Leave it unset otherwise
nonsensical (leaked kernel stack) values are returned to user space.

Signed-off-by: Nicolas Pitre <[e-mail]>
Cc: [e-mail]
Signed-off-by: Bartlomiej Zolnierkiewicz <[e-mail]>

drivers/video/console/dummycon.c

···
     .con_switch =	DUMMY,
     .con_blank =	DUMMY,
     .con_font_set =	DUMMY,
-    .con_font_get =	DUMMY,
     .con_font_default =	DUMMY,
     .con_font_copy =	DUMMY,
 };