vga: Remove remainder of old conversion cruft

All the macros used to generate different versions of vga_template.h
are now unnecessary, take them all out and remove the _32 suffix from
most functions.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>