ixgbe: Store Tx flags and protocol information to tx_buffer sooner

This change makes it so that we store the tx_flags and protocol information
to the tx_buffer_info structure sooner. This allows us to avoid unnecessary
read/write transactions since we are placing the data in the final location
earlier.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>