ccache.bbclass: Add allowed list for native recipes

ccache.bbclass: Add allowed list for native recipes

Native recipes are not able to use ccache currently, due to a circular
dependency between ccache-native and cmake-native.
This affects also other native recipes, but not all, imposing a
limitation in build time optimizations.

The introduction of CCACHE_NATIVE_RECIPES_ALLOWED allows the user to specify
which native recipes should use ccache, keeping it disable by default for all
native recipes.

Signed-off-by: Angelo Ribeiro <Angelo.Ribeiro@criticaltechworks.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>