drm: Avoid circular dependencies for CONFIG_FB

When cleaning up other drm config dependencies, it is too easy to create
larger problems. Instead, mark CONFIG_FB as a "depends":

drivers/gpu/drm/Kconfig:74:error: recursive dependency detected!

Suggested-by: Arnd Bergmann <arnd@kernel.org>
Link: https://lore.kernel.org/lkml/CAK8P3a3jUQs6c5tESSNMbqfuymewj9FhqRizyHcfOXf8Rgy-nA@mail.gmail.com/


Signed-off-by: Kees Cook <keescook@chromium.org>
[danvet: Rebase, the symbol has changed.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602215252.695994-2-keescook@chromium.org