net: ravb: Add tx/rx delay flag checks and support for rgmii-rxid
Some boards like the Beacon RZ/G2 SOM use either flags for
tx-internal-delay-ps, rx-internal-delay-ps or rgmii-rxid.
In Linux the APSR_RDM flag is set when either rx-internal-delay-ps
is set or the mode is rgmii-rxid, and the APSR_TDM is set when
tx-internal-delay-ps is found or rgmii-txid is set, and both
are set if rgmii-id is set.
The ravb driver in U-Boot driver was missing rgmii-rxid support,
so add that support in a similar fashion to what is done in Linux.