ARM: configs: remove DEBUG_LL relate configures from rockchip_linux_defconfig

ARM: configs: remove DEBUG_LL relate configures from rockchip_linux_defconfig

If we enable the kernel low-level debugging port option, then we must
assign the right UART types and PHYS address for it. But different
CPUs must have different UART configures, we can't cover all of them
in this common configure file. For example:

* RK3036 would want to chose the UART types would be RK29_UART2, and
  UART_PHYS would be 0x20068000.

* RK3228 would want to chose the UART types would be RK29_UART2, and
  UART_PHYS would be 0x11030000.

* RK3288 would want to chose the UART types would be RK32_UART2, and
  UART_PHYS would be 0xff690000.

Change-Id: I70d0da1fbffbb720b5e464acd79405624d9e7d40
Signed-off-by: Yakir Yang <ykk@rock-chips.com>