clk: X1000: Add support for the X1000 v3

[Zhou Yanjie]

v1:
1.Add the clock bindings for X1000 from Ingenic.
2.Add support for the clocks provided by the CGU in the
  Ingenic X1000 SoC.

v1->v2:
use BIT() macro instead left shift, add a call of
"ingenic_cgu_register_syscore_ops()", replace "CLK_OF_DECLARE"
with a "CLK_OF_DECLARE_DRIVER".

v2->v3:
1.Modify the wrong register in "X1000_CLK_MAC".
2.Add the clock of I2C0~I2C2.