i40evf: change type of flags variable

As pointed out by Dan Carpenter (from Oracle), the flags variable is
declared as a 64-bit long but all of the flags are defined as u32,
which may lead to unintended consequences. Fix this by declaring flags
as u32 (since we don't need any more than about a dozen flags right
now), and remove the volatile qualifier, since it's unnecessary and
just makes checkpatch cry.

Change-ID: I137d3bb1842bf7e9456b5929ca54e3b0ed45dcab
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>