x86, setup: remove obsolete pre-Kconfig CONFIG_VIDEO_ variables

There were a set of pre-Kconfig configuration variables defined in the
video code.  There is absolutely no evidence that they have been
tweaked by anybody in modern history, so just get rid of them and hope
nobody notices.  If someone does complain, these should be made real
Kconfig variables.

Reported-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>