iavf: enable symmetric-xor RSS for Toeplitz hash function

Allow the user to set the symmetric Toeplitz hash function via:

    # ethtool -X eth0 hfunc toeplitz symmetric-xor

The driver will reject any new RSS configuration if a field other than
(IP src/dst and L4 src/dst ports) is requested for hashing.

The symmetric RSS will not be supported on PFs not advertising the ADV RSS
Offload flag (ADV_RSS_SUPPORT()), for example the E700 series (i40e).

Reviewed-by: Madhu Chittim <madhu.chittim@intel.com>
Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
Link: https://lore.kernel.org/r/20231213003321.605376-9-ahmed.zaki@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>