ice: Rework flex descriptor programming

The driver can support two flex descriptor profiles, ICE_RXDID_FLEX_NIC
and ICE_RXDID_FLEX_NIC_2. This patch reworks the current flex programming
logic to add support for the latter profile.

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>