Currently, the sunxi clock driver gets the name for the base factor clock
of divs clocks from the name field in factors_data. This prevents reusing
of the factor clock for clocks with same properties, but different name.

This commit makes the divs setup function try to get a name from
clock-output-names in the devicetree. It also removes the name field where
possible and merges the sun4i PLL5 and PLL6 clocks.

[Andre: Make temporary name allocation dynamic.]
Signed-off-by: Jens Kuske <jenskuske@gmail.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>