arm/raspberrypi: Specify an initial baud rate during startup

* Fixes #5256.

* Specify an initial baud rate to use during startup.
  After the PL011 code refactor in
  0f42153959, an initial baud rate
  is required. arm_pl011_first_open is called from boot_card and
  will fail without a baud rate specified. This can cause certain
  future uses of /dev/console, such as opening a shell, to fail.

bsps/arm/raspberrypi/console/console-config.c

@@ -47,7 +47,8 @@
 #define FBCONS    "/dev/fbcons"
 
 arm_pl011_context pl011_context = {
-  .clock = 48000000
+  .clock = 48000000,
+  .initial_baud = PL011_DEFAULT_BAUD,
 };
 ns16550_context mini_uart_context;
 

bsps/arm/raspberrypi/include/bsp/usart.h

@@ -32,8 +32,6 @@
 extern "C" {
 #endif /* __cplusplus */
 
-#define PL011_DEFAULT_BAUD 115000
-#define MINI_UART_DEFAULT_BAUD   115200
 #define BCM2835_PL011_BASE (RPI_PERIPHERAL_BASE + 0x201000)
 
 #ifdef __cplusplus