This is only a test of keep u-boot logo util yocto system screen on for some request validation.
HW : 8mn-ddr4-evk.
SW: 8mn 4.14.98ga-2.2.0 release.
1. patch 2 u-boot patchs.
2. patch kernel patch.
3. changed kernel config to remove CONFIG_FRAMEBUFFER_CONSOLE and CONFIG_LOGO.