PWM setting

SDK setting is too complex, re-organize it.
void backlight_test()
{
unsigned int i,temp;

(*(volatile unsigned int *) HW_PINCTRL_MUXSEL4_CLR_ADDR) = (3<<4); // GPIO config as PWM2
(*(volatile unsigned int *) HW_PWM_ACTIVE2_CLR_ADDR) = 0; // clear count of inactive and active
(*(volatile unsigned int *) HW_PWM_ACTIVE2_SET_ADDR) = 0x00210000; // set active and inactive count
(*(volatile unsigned int *) HW_PWM_PERIOD2_CLR_ADDR) = 0; // clear
(*(volatile unsigned int *) HW_PWM_PERIOD2_SET_ADDR) = 0x000B002F; // set MATT,CDIV,INACTIVE,ACTIVE,PERIOD
(*(volatile unsigned int *) HW_CLKCTRL_XTAL_CLR_ADDR) = 0x20000000; // Clear the gate
(*(volatile unsigned int *) HW_PWM_CTRL_CLR_ADDR) = 0x40000000; // Clear the clock gate
(*(volatile unsigned int *) HW_PWM_CTRL_SET_ADDR) = (1<<5); // PWM2_ANA_CTRL_ENABLE
(*(volatile unsigned int *) HW_LRADC_CTRL0_CLR_ADDR)= 0xC0000000; // LRADC RST and gate clear
(*(volatile unsigned int *) HW_LRADC_CTRL2_CLR_ADDR)= 0x00200000; // LRADC1 feedback control

temp = (*(volatile unsigned int *) HW_LRADC_CTRL2_ADDR) & 0x001F0000;
for(i=0;i<=100;i+=10)
{
(*(volatile unsigned int *) HW_LRADC_CTRL2_ADDR) = temp | ((0x1C*i/100) << 16);
(*(volatile unsigned int *) HW_PWM_CTRL_SET_ADDR) = 0x4; // Pwm2 enable
(*(volatile unsigned int *) HW_LRADC_CTRL2_SET_ADDR) = 0x00400000; // BL enable
}
}