drm/rockchip: vop2: add missing bitfield.h include

Commit 328e6885 ("drm/rockchip: vop2: Add platform specific callback")
moved per soc configuration code to the other per-soc data into
rockchip_vop2_reg.c, but forgot to also include bitfield.h for the used
FIELD_PREP macro. Add this missing include.

Fixes: 328e6885 ("drm/rockchip: vop2: Add platform specific callback")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202503040135.fgoyWdLB-lkp@intel.com/


Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20250303182256.1727178-1-heiko@sntech.de