release: don't include nasmdoc.pdf.xz in the -xdoc file
release: don't include nasmdoc.pdf.xz in the -xdoc file

There is no reason to include both nasmdoc.pdf.xz and nasmdoc.pdf. For
the -xdoc file, the one with minimal dependencies is the proper one.

Signed-off-by: H. Peter Anvin (Intel) <8a453bad9912ffe59bc0f0b8abe03df9be19379e@zytor.com>

techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm