ice: add bitmap to track VF MSI-X usage

Create a bitamp to track MSI-X usage for VFs. The bitmap has the size of
total MSI-X amount on device, because at init time the amount of MSI-X
used by VFs isn't known.

The bitmap is used in follow up patchset to provide a block of
continuous block of MSI-X indexes for each created VF.

Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>