net/ice: refactor Rx FlexiMD handling

net/ice: refactor Rx FlexiMD handling

The hardware supports many kinds of FlexiMDs set into Rx descriptor, and
the FlexiMDs can have different offsets in the descriptor according the
DDP package setting.

The FlexiMDs type and offset are identified by the RXDID, which will be
used to setup the queue.

For expanding to support different RXDIDs in the future, refactor the Rx
FlexiMD handling by the functions mapped to related RXDIDs.

Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Acked-by: Jeff Guo <jia.guo@intel.com>