configs: stm32f469-disco: Set CYCLIC_MAX_CPU_TIME_US to 50000 for stm32f469-disco

Updating the framebuffer takes quite a long time on this slow patform,
set CYCLIC_MAX_CPU_TIME_US to 50000 for stm32f469-disco to avoid
following cyclic warning:

"cyclic function video_init took too long: 46784us vs 5000us max"

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
1 file changed