tools: remove easylogo and include/video_logo.h

include/video_logo.h once was created via the tool easylogo and than used
in cpu/mpc8xx/video.c to display Tux. video_logo.h has been replaced by
include/linux_logo.h and is not needed anymore.

Delete the include and the tool,

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>