[PATCH] x86: "make isoimage" support; FDINITRD= support; minor cleanups

Add a "make isoimage" to i386 and x86-64, which allows the automatic
creation of a bootable CD image.  It also adds an option FDINITRD= to
include an initrd of the user's choice in generated floppy- or CD boot
images.  Finally, some minor cleanups of the image generation code.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>