qed: Correct HW stop flow

Management firmware is used as arbiter between different PFs
which are loading/unloading, but in order to use the synchronization
it offers the contending configurations need to be applied either
between their LOAD_REQ <-> LOAD_DONE or UNLOAD_REQ <-> UNLOAD_DONE
management firmware commands.

Existing HW stop flow utilizes 2 different functions: qed_hw_stop() and
qed_hw_reset() which don't abide this requirement; Most of the closure
is doing outside the scope of the unload request.

This patch removes qed_hw_reset() and places the relevant stop
functionality underneath the management firmware protection.

Signed-off-by: Tomer Tayar <Tomer.Tayar@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>