clk: Ingenic: Add CGU driver for X1830.

Add support for the clocks provided by the CGU in the Ingenic X1830
SoC, making use of the cgu code to do the heavy lifting.

Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lkml.kernel.org/r/20200528031549.13846-6-zhouyanjie@wanyeetech.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>