A recent addition exposed a helper that is only used for CONFIG_OF. Move
it into the CONFIG_OF zone in this file to make the compiler stop
warning about an unused function.

Fixes: 66d95064 ("clk: walk orphan list on clock provider registration")
Signed-off-by: Olof Johansson <olof@lixom.net>
Link: https://lkml.kernel.org/r/20191217082501.424892072D@mail.kernel.org
[sboyd@kernel.org: "Simply" move the function instead]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>