fbdev/chipsfb.c:401:31: error: invalid use of undefined type 'struct backlight_device'

[Naresh Kamboju]

The powerpc ppc6xx_defconfig builds failed on today's Linux next tag
next-20240304.

Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

Build log:
---------
drivers/video/fbdev/chipsfb.c: In function 'chipsfb_pci_init':
drivers/video/fbdev/chipsfb.c:401:31: error: invalid use of undefined
type 'struct backlight_device'
  401 |                 pmac_backlight->props.power = FB_BLANK_UNBLANK;
      |                               ^~

Steps to reproduce:
 # tuxmake --runtime podman --target-arch powerpc --toolchain gcc-13
--kconfig ppc6xx_defconfig
 - https://storage.tuxsuite.com/public/linaro/lkft/builds/2dDE297yLFrAr3gigIDy8tIleDh/tuxmake_reproducer.sh

Links:
- https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240304/testrun/22919857/suite/build/test/gcc-13-ppc6xx_defconfig/details/
- https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240304/testrun/22919857/suite/build/test/gcc-13-ppc6xx_defconfig/log
- https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240304/testrun/22919857/suite/build/test/gcc-13-ppc6xx_defconfig/history/


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Linaro LKFT
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