i40e: Make the DCB firmware checks for X710/XL710 only

Make the DCB firmware version related checks specific to
X710 and XL710 only. These checks are not required for
X722 family of devices.

Introduced an inline routine to help determine if the
MAC type is X710/XL710 or not.

Moved the firmware version related checks in i40e_sw_init()
and defined flags for different cases

Fix the version check to allow using "Set LLDP MIB" AQ
for beyond FVL4 FW releases.

Change-ID: Ib78288343de983aa0354fc28aa36e99b073662c0
Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>