Test to keep u-boot logo util system screen on.

[#1]

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.