regulator: qcom_pm8008: allow multiple PM8008 instances with unique names

Change the qcom_pm8008-regulator "regulator-name" device tree
property parsing procedure from an exact match to a substring
match.  This allows multiple PM8008 chips to be used on a given
board which have unique names specified for their respective
regulators.

Change-Id: I519107431148cdf1882d8e50056f2d2e20ce018f
Signed-off-by: David Collins <collinsd@codeaurora.org>