soc/bman: Add self-test for BMan driver

Add a self test for the DPAA 1.x Buffer Manager driver. This
test ensures that the driver can properly acquire and release
buffers using the BMan portal infrastructure.

Signed-off-by: Roy Pledge <roy.pledge@nxp.com>
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Scott Wood <oss@buserror.net>