arm: omap5+: Add support for early debug

For early debug, the following configs needs to be enabled:

CONFIG_DEBUG_UART=y
CONFIG_DEBUG_UART_OMAP=y
CONFIG_DEBUG_UART_CLOCK=48000000
CONFIG_DEBUG_UART_SHIFT=2
CONFIG_DEBUG_UART_ANNOUNCE=y

For DRA7xx:
CONFIG_DEBUG_UART_BASE=0x4806a000

For AM57xx:
CONFIG_DEBUG_UART_BASE=0x48020000

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/mach-omap2/hwinit-common.c

@@ -12,6 +12,7 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
+#include <debug_uart.h>
 #include <spl.h>
 #include <asm/arch/sys_proto.h>
 #include <linux/sizes.h>
@@ -159,6 +160,9 @@ void early_system_init(void)
 	setup_early_clocks();
 	do_board_detect();
 	vcores_init();
+#ifdef CONFIG_DEBUG_UART_OMAP
+	debug_uart_init();
+#endif
 	prcm_init();
 }