phy: sun4i-usb: Add Allwinner R40 support

Since every Allwinner USB PHY seems to be slightly different from each
other, we need to add the compatible string and the respective data
structure to make it work on the R40/V40 SoC.
Nothing spectacular this time, just one less USB controller than the H3.
Copied from the Linux kernel.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
index 16d41b8..3a3b673 100644
--- a/arch/arm/mach-sunxi/Kconfig
+++ b/arch/arm/mach-sunxi/Kconfig
@@ -250,6 +250,7 @@
 	select SUPPORT_SPL
 	select SUNXI_DRAM_DW
 	select SUNXI_DRAM_DW_32BIT
+	select PHY_SUN4I_USB
 
 config MACH_SUN8I_V3S
 	bool "sun8i (Allwinner V3s)"