layer.conf: Don't use indirect help2man-native dependencies

Similarly to other tools such as pkgconfig and quilt, don't pull in
help2man-native unless there is a direct DEPENDS. This is generally good
for keeping the recipe sysroots leaner and cleaner and should fix some
issues with squashf-tools in particular.

This will mean any recipe with an indirect dependency will break so
missing recipe dependencies will need to be fixed.

(From OE-Core rev: df4e37ef888ad11f98c2f17ab4bc48dbd5417790)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/conf/layer.conf

@@ -103,6 +103,7 @@ SSTATE_EXCLUDEDEPS_SYSROOT += "\
     .*->quilt-native \
     ^(?!gtk-doc-native).*->xmlto-native \
     .*->gperf-native \
+    .*->help2man-native \
     .*->gtk-doc-native \
     .*->texinfo-native \
     .*->perlcross-native \