serial: a37xx: Use CONFIG_BAUDRATE for initializing early debug UART

CONFIG_BAUDRATE should be used for setting the baudrate for the early debug
UART. This replaces current hardcoded 115200 value.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behun <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/serial/serial_mvebu_a3700.c b/drivers/serial/serial_mvebu_a3700.c
index c7e66fe..52dc3fd 100644
--- a/drivers/serial/serial_mvebu_a3700.c
+++ b/drivers/serial/serial_mvebu_a3700.c
@@ -309,7 +309,7 @@
 static inline void _debug_uart_init(void)
 {
 	void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
-	u32 baudrate, parent_rate, divider;
+	u32 parent_rate, divider;
 
 	/* reset FIFOs */
 	writel(UART_CTRL_RXFIFO_RESET | UART_CTRL_TXFIFO_RESET,
@@ -322,9 +322,8 @@
 	 * Calculate divider
 	 * baudrate = clock / 16 / divider
 	 */
-	baudrate = 115200;
 	parent_rate = get_ref_clk() * 1000000;
-	divider = DIV_ROUND_CLOSEST(parent_rate, baudrate * 16);
+	divider = DIV_ROUND_CLOSEST(parent_rate, CONFIG_BAUDRATE * 16);
 	writel(divider, base + UART_BAUD_REG);
 
 	/*