Remove old ARM cross-compilation (2004)

Software versions are totally out-of-date.
Platforms don't even exist anymore.
And this predated ARM support in the contrib.

doc/Makefile.am

@@ -33,7 +33,6 @@ EXTRA_DIST = \
 	fortunes.txt \
 	intf-vcd.txt \
 	release-howto.txt \
-	arm-crosscompile-howto.sgml \
 	Doxyfile.in \
 	lirc/example.lircrc \
 	skins/skins-howto.txt \