drm/fb_helper: Rename field fbdev to info in struct drm_fb_helper

Rename struct drm_fb_helper.fbdev to info. The current name is
misleading as it overlaps with generic fbdev naming conventions.
Adapt to the usual naming in fbdev drivers by calling the field
'info'. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221103151446.2638-13-tzimmermann@suse.de