Added means to configure libftl to use (optionally) another bdev as
persistent write buffer cache.
Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: I97028a681be168d9386eac8a226631ff772f803b
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/448629
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>