platform_data: Add linux/platform_data/tps68470.h file

The clk and regulator frameworks expect clk/regulator consumer-devices
to have info about the consumed clks/regulators described in the device's
fw_node.

To work around cases where this info is not present in the firmware tables,
which is often the case on x86/ACPI devices, both frameworks allow the
provider-driver to attach info about consumers to the provider-device
during probe/registration of the provider device.

The TI TPS68470 PMIC is used x86/ACPI devices with the consumer-info
missing from the ACPI tables. Thus the tps68470-clk and tps68470-regulator
drivers must provide the consumer-info at probe time.

Define tps68470_clk_platform_data and tps68470_regulator_platform_data
structs to allow the x86 platform code to pass the necessary consumer info
to these drivers.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20211203102857.44539-5-hdegoede@redhat.com