dts: keep clock-names and clocks in SPL DTB if SPL_CLK is enabled

These two properties are necessary for SPL to get clocks from DT.

Note:
For now, only clock look-up by index is supported (clk_get_by_index()
function), so "clock-names" is never parsed in U-Boot.  However, we
may want to support something like clk_get_by_name() in the future,
so let's keep "clock-names" as well as "clocks".

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

dts/Kconfig

@@ -61,7 +61,9 @@ config DEFAULT_DEVICE_TREE
 config OF_SPL_REMOVE_PROPS
 	string "List of device tree properties to drop for SPL"
 	depends on SPL_OF_CONTROL
+	default "interrupt-parent" if SPL_PINCTRL_FULL && SPL_CLK
 	default "clocks clock-names interrupt-parent" if SPL_PINCTRL_FULL
+	default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK
 	default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent"
 	help
 	  Since SPL normally runs in a reduced memory space, the device tree