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>