mvpp2: remove module bugfix

The remove function does not destroy all
BM Pools when per cpu pool is active.

When reloading the mvpp2 as a module the BM Pools
are still active in hardware and due to the bug
have twice the size now old + new.

This eventually leads to a kernel crash.

v2:
* add Fixes tag

Fixes: 7d04b0b1

 ("mvpp2: percpu buffers")
Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de>
Signed-off-by: David S. Miller <davem@davemloft.net>