PCI: rcar: Don't disable/unprepare clocks on prepare/enable failure

If clk_prepare_enable() fails, we must not call clk_disable_unprepare() in
the error path.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>