ccache: deprecate the target package

Since we have deprecated the capability of building a toolchain for
the target, it makes sense to also deprecate ccache for the target.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/ccache/Config.in

@@ -2,6 +2,8 @@ config BR2_PACKAGE_CCACHE
 	bool "ccache"
 	# needs fork()
 	depends on BR2_USE_MMU
+	# We no longer support a toolchain on the target
+	depends on BR2_DEPRECATED
 	help
 	  ccache is a compiler cache. It speeds up recompilation by
 	  caching previous compilations and detecting when the same