pl111: Rename the pl111 driver to "kmsro".

pl111: Rename the pl111 driver to "kmsro".

The vc4 driver can do prime sharing to many different KMS-only devices,
such as the various tinydrm drivers for SPI-attached displays.  Rename the
driver away from "pl111" to represent what it will actually support:
various sorts of KMS displays with the renderonly layer used to attach a
GPU.

Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Acked-by: Emil Velikov <emil.velikov@collabora.com>