how to change uart0->uart1 to debug board on r8

[tracewong]

1.edit sys_config.fex for board
file path:package/boot/uboot-sun5i/bootloader/sun5i/configs/{boards}/sys_config.fex
change mainkey [uart_para] as follow
[uart_para]
uart_debug_port = 1
uart_debug_tx = port:PG3<4><1>
uart_debug_rx = port:PG4<4><1>
2.edit env.cfg
file path:package/boot/uboot-sun5i/env.cfg
change "console=ttyS0,115200" to "console=ttyS1,115200"
3.edit inittab
file path:/target/linux/sun5i/base-files/etc/inittab
change "ttyS0::askfirst:/bin/ash --login" to "ttyS1::askfirst:/bin/ash --login"