[ Upstream commit d484e06e25ebb937d841dac02ac1fe76ec7d4ddd ]

Fix below issues in err code path of probe:
1. we don't need to unregister_netdev() because the netdev isn't
registered.
2. when register_netdev() fails, we also need to destroy bm pool for
HWBM case.

Fixes: dc35a10f ("net: mvneta: bm: add support for hardware buffer management")
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>