Set DEBUG_LL_UART_DIVISOR to use <asm/debug_ll_ns16550.h>.
The JZ4755 uses 24 MHz as the main reference frequency (EXCLK).
The UART controller can work on full EXCLK or on EXCLK/2.
Just now we use EXCLK/2 legacy clock setup made by U-Boot.
So set UART controller base frequency to 12 MHz.
Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>