This is a port of commit 248de22e ("i40e/i40evf: Account for frags
split over multiple descriptors in check linearize")

As part of testing workloads (read/write) using larger IO size (128K)
tx_timeout is observed and whenever it happens, it was due to
tx_linearize.
Signed-off-by: Kiran Patil <kiran.patil@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>