i40e: Fix state flags for bit set and clean operations of PF

Commit 0da36b97 ("i40e: use DECLARE_BITMAP for state fields")
introduced changes in the way i40e works with state flags converting
them to bitmaps using kernel bitmap API. This change introduced a
regression due to a mistaken substitution using __I40E_VSI_DOWN instead
of __I40E_DOWN when testing state of a PF at i40e_reset_subtask()
function. This caused a flood in the kernel log with the follow message:

[49.013] i40e 0002:01:00.0: bad reset request 0x00000020

Commit d19cb64b ("i40e: separate PF and VSI state flags")
also introduced some misuse of the VSI and PF flags, so both could be
considered as the offenders.

This patch simply fixes the flags where it makes sense by changing
__I40E_VSI_DOWN to __I40E_DOWN.

Fixes: 0da36b97 ("i40e: use DECLARE_BITMAP for state fields")
Fixes: d19cb64b

 ("i40e: separate PF and VSI state flags")

Reviewed-by: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: "Mauro S. M. Rodrigues" <maurosr@linux.vnet.ibm.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>