backlight/lv5207lp: Compare against struct fb_info.device

backlight/lv5207lp: Compare against struct fb_info.device

Struct lv5207lp_platform_data refers to a platform device within
the Linux device hierarchy. The test in lv5207lp_backlight_check_fb()
compares it against the fbdev device in struct fb_info.dev, which
is different. Fix the test by comparing to struct fb_info.device.

Fixes a bug in the backlight driver and prepares fbdev for making
struct fb_info.dev optional.

v2:
	* move renames into separate patch (Javier, Sam, Michael)

Fixes: 82e5c40d88f9 ("backlight: Add Sanyo LV5207LP backlight driver")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Lee Jones <lee@kernel.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: linux-sh@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v3.12+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-6-tzimmermann@suse.de