dt-bindings: mfd: bd72720: Add ROHM BD73900

dt-bindings: mfd: bd72720: Add ROHM BD73900

The ROHM BD79300 is almost identical to the BD72720. Main differences
are the initial values for some of the registers. Thus, it appears the
BD79300 can be handled with same software as BD72720.

Adding the compatible for the BD79300 enables people to use the real IC
type in the device-tree instead of claiming it is BD72720. This does
also help differentiating the ICs if appears it is needed.

Add own compatible for the BD73900 and mark BD72720 as a fall-back.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/6eaa9f08848c27c462e156e31ae5bdfd33bf2fe7.1771938507.git.mazziesaccount@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>