feat(console): introduce EARLY_CONSOLE

This is a generic porting of what was done on ST platforms with flag
STM32MP_EARLY_CONSOLE. It creates the flag and the prototype for
plat_setup_early_console(). This function depends on platform
implementation. This function call is added at the beginning of each BL
image early setup function.
The patch also introduce an extra log macro: EARLY_ERROR. This can
replace ERROR macro in code that will only be executed before the
default console is enabled, and will do nothing when the EARLY_CONSOLE
is not enabled. This can then save some space in memory.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I77bf0a0c4289b4c7df94e4bfb783a938e05bf023
diff --git a/bl2/bl2_main.c b/bl2/bl2_main.c
index 923a554..3df0bfa 100644
--- a/bl2/bl2_main.c
+++ b/bl2/bl2_main.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -41,6 +41,9 @@
 void bl2_el3_setup(u_register_t arg0, u_register_t arg1, u_register_t arg2,
 		   u_register_t arg3)
 {
+	/* Enable early console if EARLY_CONSOLE flag is enabled */
+	plat_setup_early_console();
+
 	/* Perform early platform-specific setup */
 	bl2_el3_early_platform_setup(arg0, arg1, arg2, arg3);
 
@@ -63,6 +66,9 @@
 void bl2_setup(u_register_t arg0, u_register_t arg1, u_register_t arg2,
 	       u_register_t arg3)
 {
+	/* Enable early console if EARLY_CONSOLE flag is enabled */
+	plat_setup_early_console();
+
 	/* Perform early platform-specific setup */
 	bl2_early_platform_setup2(arg0, arg1, arg2, arg3);