feat(common/debug): add new macro ERROR_NL() to print just a newline

Existing macro ERROR() prints string "ERROR" followed by string
specified by caller. Therefore via this existing macro it is not
possible to end incomplete / existing line by a newline character.

This change adds a new macro ERROR_NL() which prints just a newline
character without any prefix. Implementation of this macro is done via a
new function tf_log_newline() which based on supplied log level either
return or print newline character.

If needed in future based on this tf_log_newline() function can be
defined also macros for other log levels.

Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I05414ca177f94cdc0f6077394d9c4af4a4382306
diff --git a/include/common/debug.h b/include/common/debug.h
index ed0e8bf..a7ca0d7 100644
--- a/include/common/debug.h
+++ b/include/common/debug.h
@@ -61,8 +61,10 @@
 
 #if LOG_LEVEL >= LOG_LEVEL_ERROR
 # define ERROR(...)	tf_log(LOG_MARKER_ERROR __VA_ARGS__)
+# define ERROR_NL()	tf_log_newline(LOG_MARKER_ERROR)
 #else
 # define ERROR(...)	no_tf_log(LOG_MARKER_ERROR __VA_ARGS__)
+# define ERROR_NL()
 #endif
 
 #if LOG_LEVEL >= LOG_LEVEL_NOTICE
@@ -109,6 +111,7 @@
 void __dead2 __stack_chk_fail(void);
 
 void tf_log(const char *fmt, ...) __printflike(1, 2);
+void tf_log_newline(const char log_fmt[2]);
 void tf_log_set_max_level(unsigned int log_level);
 
 #endif /* __ASSEMBLER__ */