linux-phytec-ti

soc: ti: pruss: Drop MII-RT management from PRUSS driver

The MII-RT sub-module is represented as a syscon node and is
managed by the PRUSS platform driver at the moment. The usage
of MII-RT is limited to PRU Ethernet drivers, and so makes sense
to manage this sub-module by those drivers directly. So, drop
the code from the PRUSS platform driver that deals with parsing
of the mii-rt DT nodes or providing an API wrapper for accessing
any registers within this sub-module.

Signed-off-by: Suman Anna <s-anna@ti.com>