When using hob ui interface, we need extra cache fields.
We will save ui required extra cache fields into a separate
cache file. This patch introduce this caches_array parameter.
It will be used in the extra cache implementation (following patch).
Caches_array at least contains CoreRecipeInfo. If users need extra
cache fields support, such as 'hob', caches_array will contain
more relevant elements such as HobRecipeInfo.
(Bitbake rev: d50389ae692377c957afec7c846fc2ce2c070a09)
Signed-off-by: Liping Ke <liping.ke@intel.com>