If clk_fetch_parent_index() fails, p_rate is unused.  Move the
assignment after the error checking.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NVladimir Zapolskiy <vz@mleia.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>