MIPS,clk: migrate JZ4740 to common clock framework

Migrate the JZ4740 & the qi_lb60 board to use common clock framework
via the new Ingenic SoC CGU driver. Note that the JZ4740-specific
debugfs code is removed since common clock framework provides its own
debug capabilities.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Co-authored-by: Paul Cercueil <paul@crapouillou.net>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: devicetree@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: linux-kernel@vger.kernel.org
Cc: Brian Norris <computersforpeace@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10151/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/boot/dts/ingenic/jz4740.dtsi

@@ -1,3 +1,5 @@
+#include <dt-bindings/clock/jz4740-cgu.h>
+
 / {
 	#address-cells = <1>;
 	#size-cells = <1>;
@@ -20,4 +22,25 @@
 		interrupt-parent = <&cpuintc>;
 		interrupts = <2>;
 	};
+
+	ext: ext {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+	};
+
+	rtc: rtc {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <32768>;
+	};
+
+	cgu: jz4740-cgu@10000000 {
+		compatible = "ingenic,jz4740-cgu";
+		reg = <0x10000000 0x100>;
+
+		clocks = <&ext>, <&rtc>;
+		clock-names = "ext", "rtc";
+
+		#clock-cells = <1>;
+	};
 };

arch/mips/boot/dts/ingenic/qi_lb60.dts

@@ -5,3 +5,7 @@
 / {
 	compatible = "qi,lb60", "ingenic,jz4740";
 };
+
+&ext {
+	clock-frequency = <12000000>;
+};