sh: ecovec24: Rename missed backlight field from fbdev to dev

sh: ecovec24: Rename missed backlight field from fbdev to dev

One instance of gpio_backlight_platform_data.fbdev was renamed, but the
second instance was forgotten, causing a build failure:

    arch/sh/boards/mach-ecovec24/setup.c: In function ‘arch_setup’:
    arch/sh/boards/mach-ecovec24/setup.c:1223:37: error: ‘struct gpio_backlight_platform_data’ has no member named ‘fbdev’; did you mean ‘dev’?
     1223 |                 gpio_backlight_data.fbdev = NULL;
	  |                                     ^~~~~
	  |                                     dev

Fix this by updating the second instance.

Fixes: ed369def91c1579a ("backlight/gpio_backlight: Rename field 'fbdev' to 'dev'")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202309231601.Uu6qcRnU-lkp@intel.com/
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/20230925111022.3626362-1-geert+renesas@glider.be
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>