ccache.bbclass: use ccache from host distribution

ccache 4.x has hard dependencies on cmake-native (used as
build system) and zstd, which means inserting ccache-native
as DEPENDS into everything creates circular dependencies which
are impossible to break.

ccache 3.x did not have this problem as it used plain makefiles
and an in-tree copy of zlib.

(From OE-Core rev: f5b29367af4d8e5daea5771264774aa49519f9a8)

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/ccache.bbclass

@@ -1,5 +1,7 @@
 #
 # Usage:
+# - Install ccache package on the host distribution and set up a build directory
+#
 # - Enable ccache
 #   Add the following line to a conffile such as conf/local.conf:
 #   INHERIT += "ccache"
@@ -47,7 +49,6 @@ python() {
     # quilt-native doesn't need ccache since no c files
     if not (pn in ('ccache-native', 'quilt-native') or
             bb.utils.to_boolean(d.getVar('CCACHE_DISABLE'))):
-        d.appendVar('DEPENDS', ' ccache-native')
         d.setVar('CCACHE', 'ccache ')
 }