soc: fsl: dpio: add frame list format support

Add support for dpaa2_fd_list format, i.e. dpaa2_fl_entry structure
and accessors.

Frame list entries (FLEs) are similar, but not identical to FDs:
+ "F" (final) bit
- FMT[b'01] is reserved
- DD, SC, DROPP bits (covered by "FD compatibility" field in FLE case)
- FLC[5:0] not used for stashing

Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Acked-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>