ARM: DRA7: Add support for soc_is_dra74x() and soc_is_dra72x() varients

Use the corresponding compatibles to identify the devices.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
ARM: DRA7: hwmod: Add dra74x and dra72x specific ocp interface lists

To deal with IPs which are specific to dra74x and dra72x, maintain seperate
ocp interface lists, while keeping the common list for all common IPs.

For now move USB OTG SS4 to dra74x only list since its unavailable in
dra72x. The dra72x only list is empty for now and a placeholder for
future hwmod additions for CAL etc which are specific to dra72x.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>