regulator: Extend of_get_regulator_init_data to support non-DT consumers

Extend the of_get_regulator_init_data function so that it can
parse an additional property from regulator device tree nodes
which is needed to support non-device tree consumers.

The new property is named qcom,consumer-supplies.  Its value
is a list of strings of the form:

qcom,consumer-supplies = "supply_name1", "device_name1",
                         "supply_name2", "device_name2", ...

Change-Id: Ia689d04e6de568e6889b807eed15df3116de01d2
Signed-off-by: David Collins <collinsd@codeaurora.org>