adv7842自定义方式

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1. sav = hsyc + h_backproch(后廊) -4
   = 44 + 76 - 4
   = 116
   eav = h_total - h_frontporch（前廊）
   = 2050- 10
   = 2040
   start_vbi = v_total - vfrontporch（前廊） + 1
   = 1105- 4 + 1
   = 1102
   end_vbi = vsync + vbackporch(后廊) + 1
   = 5 + 16 +1
   = 22
   2050 h
   1105 v
2. ch1_fr_ll = (width * (ADV7842_fsc / 100)) / ((u32)bt->pixelclock / 100))
   =（2050x28.6363/100）= 549816960/1350000=407
   cp_write(sd, 0x8f, (ch1_fr_ll >> 8) & 0x7);
   cp_write(sd, 0x90, ch1_fr_ll & 0xff);
   注：ADV7842_fsc 外部晶振频率
3. adv7842第一路存在噪点，修改adv7842_write(dev,IO_MAP, 0x19, 0x9f) dll改为最大值，1f（5bit）