drm/amd/display: Add dm_logger_append_va API

Same as dm_logger_append, except it takes a va_list instead of a
variable number of arguments. dm_logger_append is now a minimal wrapper
around dm_logger_append_va.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/include/logger_interface.h

@@ -57,6 +57,11 @@ void dm_logger_append(
 		const char *msg,
 		...);
 
+void dm_logger_append_va(
+		struct log_entry *entry,
+		const char *msg,
+		va_list args);
+
 void dm_logger_open(
 		struct dal_logger *logger,
 		struct log_entry *entry,