qede: Revise state locking scheme

As qede utilizes an internal-reload sequence as result of various
configuration changes, the netif state wouldn't always accurately describe
the status of the configuration.
To compensate, we're storing an internal state of the device, which should
only be accessed under the qede_lock.

This patch fixes and improves several state/lock interactions:
  - The internal state should only be checked while locked.
  - While holding lock, it's preferable to check state rather than
    the netdevice's state.
  - The reload sequence is not 'atomic' - unload and subsequent load
    are not in the same critical section.

This also add the 'locked' variant for the reload, which would later be
used by XDP - useful in the case where the correct sequence is 'lock,
check state and re-configure if good', instead of allowing the reload
itself to make the decision regarding the configurability of the device.

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