plugins/cache: Added FIFO and LRU eviction policies

Implemented FIFO and LRU eviction policies. Now one of the three
eviction policies can be chosen as an argument. On not specifying an
argument, LRU is used by default.

Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210623125458.450462-4-ma.mandourr@gmail.com>
Message-Id: <20210709143005.1554-39-alex.bennee@linaro.org>