soc: fsl: dpio: add back some frame queue functions

This commit adds back functions removed in
commit a211c817 ("staging: fsl-mc/dpio: remove couple of unused functions")
since dpseci object will make use of them.

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