The L3 cache controller (Corenet Platform Cache) is listed with one of its
compatible strings as "cache", which this driver can't attach to. Restrict
to a known list of primary cache controller strings, as found in the l2cache
devicetree binding.
Some PowerQUICC and QorIQ platforms have a L2 cache managed via the
memory-mapped configuration registers, and appear as a node in the device
tree. This adds basic support to enable the cache.
