net/ixgbevf: fix max packet length

net/ixgbevf: fix max packet length

Current ixgbevf driver get max_rx_pktlen = 15872, but in fact PF
supports 15872-byte jumbo frame and VF only supports 9728-byte jumbo
frame. If VF is running DPDK driver and set frame_size > 9728 ,PF
running kernel ixgbe driver will report an error and set VF failed.
This patch fixs DPDK ixgbevf driver to get correct jumbo frame size
of VF.

More datasheet references from Wei Dai:

In 82599 datasheet, there is an annotation in the chapter 1.3 Features
Summary (page 29)
 The 82599 supports full-size 15.5 KB (15872-byte) jumbo packets while
 in a basic mode of operation. When DCB mode is enabled,
 or security engines enabled or virtualization is enabled, the 82599
 supports 9.5 KB (9728-byte) jumbo packets.

In x540 datasheet, there is also an annotation in the chapter 1.3
Features Summary (page 13)
 The X540 and 82599 support full-size 15.5 KB jumbo packets while in a
 basic mode of operation. When DCB mode is enabled,
 or security engines enabled, or virtualization is enabled, or OS2BMC is
 enabled, then the X540 supports 9.5 KB jumbo packets.
 Packets to/from MC longer than 2KB are filtered out.

In x550 datasheet, there is still also an annotation in the chapter 1.4
Feature Summary (page 23)
 All the products support full-size 15.5 KB jumbo packets while in a
 basic mode of operation. When DCB mode is enabled, or security
 engines enabled, or virtualization is enabled, or OS2BMC is enabled,
 then only 9.5 KB jumbo packets are supported. Packets to/
 from the MC longer than 2 KB are filtered out.

Fixes: 2144f6630fca ("ixgbe: add redirection table size in device info")
Cc: stable@dpdk.org
Signed-off-by: Yi Zhang <zhang.yi75@zte.com.cn>
Acked-by: Wei Dai <wei.dai@intel.com>