of: Add of_property_match_string() to find index into a string list

of: Add of_property_match_string() to find index into a string list

commit 7aff0fe33033fc75b61446ba29d38b1b1354af9f upstream.

Add a helper function for finding the index of a string in a string
list property.  This helper is useful for bindings that use a separate
*-name property for attaching names to tuples in another property such
as 'reg' or 'gpios'.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
[jt: dropped changes to files not existing in the 3.2 tree]
Signed-off-by: Jonathan Toppins <jtoppins@cumulusnetworks.com>
Reviewed-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Acked-by: Curt Brune <curt@cumulusnetworks.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>