ice: initialize mailbox snapshot earlier in PF init

ice: initialize mailbox snapshot earlier in PF init

Now that we no longer depend on the number of VFs being allocated, we can
move the ice_mbx_init_snapshot function earlier. This will be required by
Scalable IOV as we will not be calling ice_sriov_configure for Scalable
VFs.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Marek Szlosek <marek.szlosek@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>