video: Assume video to be active if SPL is passing video hand-off

If SPL is passing video handoff structure to U-boot then it is safe to
assume that SPL has already enabled video and that's why it is passing
video handoff structure to U-boot so that U-boot can preserve the
framebuffer.

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