ixgbevf: make sure all frames fit minimum size requirements

Similar to commit a50c29dd
("ixgbe: Make certain that all frames fit minimum size requirements")

Make sure that any packet we attempt to transmit will meet minimum
size requirements.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>