of: Remove prefix "__of_" from local function names

Remove "__of_" prefix from local function names.  The pattern of
a leading "__" is used in drivers/of/ to signify a function that
must be called with a lock held.  These functions do not fit
that pattern.

Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>