net/i40e: fix VF reset flow

net/i40e: fix VF reset flow

Add missing step during VF reset: PF should
set I40E_VFGEN_RSTAT to ACTIVE at end of the
VF reset operation or VF driver may not able
to detect that reset is already completed.
This patch also remove the unnecessary enum
for vfr state.

Fixes: 4861cde46116 ("i40e: new poll mode driver")

Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Helin Zhang <helin.zhang@intel.com>
Acked-by: Vincent Jardin <vincent.jardin@6wind.com>