ixgbe: allow to increase MTU to 3K with XDP enabled

ixgbe: allow to increase MTU to 3K with XDP enabled

commit e76e182f80875ee7fec0c3e92adf01faa9f46b9e upstream.

Recently I encountered one case where I cannot increase the MTU size
directly from 1500 to a much bigger value with XDP enabled if the
server is equipped with IXGBE card, which happened on thousands of
servers in production environment. After applying the current patch,
we can set the maximum MTU size to 3K.

This patch follows the behavior of changing MTU as i40e/ice does.

References:
[1] commit 53b5f8f08a03 ("ice: allow 3k MTU for XDP")
[2] commit 30067ecaebfe ("i40e: add XDP support for pass and drop actions")

Fixes: e6d3c7b58f9d ("ixgbe: Prevent unsupported configurations with XDP")
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>