The ROHM BD71847 PMIC has a 32.768 kHz clock.  Adding necessary parent
allows to probe the bd718x7 clock driver fixing boot errors:

    bd718xx-clk bd71847-clk.1.auto: No parent clk found
    bd718xx-clk: probe of bd71847-clk.1.auto failed with error -22
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>