I2C 调整CLK

1. 直接改code

   在驱动ms_iic.c里mstar_i2c_probe（）改i2c_speed，默认是int i2c_speed = E_HWI2C_NORMAL;

2. 可以在对应dtsi的i2c节点里增加：i2c-speed = <0>;驱动会去读dts的节点。(推荐)

   typedef enum _HWI2C_CLKSEL
   {
       E_HWI2C_HIGH = 0, /// high speed 400K
       E_HWI2C_NORMAL, /// normal speed 300K
       E_HWI2C_SLOW, /// slow speed 200K
       E_HWI2C_VSLOW, /// very slow 100K
       E_HWI2C_USLOW, /// ultra slow 50K
       E_HWI2C_UVSLOW, /// ultra-very slow 25K
       E_HWI2C_NOSUP /// non-support speed
   }HWI2C_CLKSEL;