mfd: hi655x: Add the clock cell to provide WiFi and Bluetooth

The hi655x is a PMIC with regulator but also provides a clock for the WiFi
and the bluetooth which is missing in the current implementation.

Add the clock cell so it can be used in the next patch via the dts.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>