drm: xlnx: zynqmp_dpsub: Fix compilation error

Fix W=1 clang 19 compilation error in zynqmp_disp_layer_drm_formats().

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404260946.4oZXvHD2-lkp@intel.com/



Signed-off-by: Anatoliy Klymenko <anatoliy.klymenko@amd.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240426-dp-live-fmt-fix-v3-2-e904b5ae51d7@amd.com