usb: musb: dsps: switch to static id for musb-hdrc platform devices

usb: musb: dsps: switch to static id for musb-hdrc platform devices

The dsps glue uses PLATFORM_DEVID_AUTO when creating the musb-hdrc
platform devices, this causes that the id will change in each system
depending on the order of driver probe, the order of the usb instances
defined in device-tree, or the list of enabled devices which use also
PLATFORM_DEVID_AUTO in kernel config. This id inconsistency causes
trouble in shell scripting or user guide documentation.

So switch it to static id, starting from 0 to the musb instance with
lower MMR offset. This scheme is also aligned to the naming in the SoC.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>