clk: gxbb: add AmLogic GXBB clk controller driver

The gxbb clock controller is the primary clock generation unit for the
AmLogic GXBB SoC. It is clocked by a fixed 24MHz xtal, contains several
PLLs and the usual post-dividers, muxes, dividers and leaf gates that
are fed into various IP blocks in the SoC.

Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>

include/dt-bindings/clock/gxbb-clkc.h

@@ -0,0 +1,12 @@
+/*
+ * GXBB clock tree IDs
+ */
+
+#ifndef __GXBB_CLKC_H
+#define __GXBB_CLKC_H
+
+#define CLKID_CPUCLK		1
+#define CLKID_CLK81		12
+#define CLKID_ETH		36
+
+#endif /* __GXBB_CLKC_H */