common: spl: spl: Remove video driver before u-boot proper

Add method to remove video driver before loading u-boot proper. When
bootstage changes from SPL to u-boot proper, noo method is called to
remove video driver, and at u-boot proper if video driver is not
enabled, the video driver starts displaying garbage on the screen,
because there is no reserved space for video and the frame buffer gets
u-boot proper data written.

Signed-off-by: Nikhil M Jain <n-jain1@ti.com>