console: Declare empty printk() for __ROMCC__

The typical do { } while (0) did not work, so
provide empty stub function instead.

Change-Id: Ieb0c33b082b4c4453d29d917f46561c0e672d09a
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35588
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/include/console/console.h

@@ -19,7 +19,6 @@
 #include <stdint.h>
 #include <arch/cpu.h>
 #include <console/post_codes.h>
-#include <console/vtxprintf.h>
 
 /* console.h is supposed to provide the log levels defined in here: */
 #include <commonlib/loglevel.h>
@@ -29,6 +28,8 @@
 
 #ifndef __ROMCC__
 
+#include <console/vtxprintf.h>
+
 void post_code(u8 value);
 #if CONFIG(CMOS_POST_EXTRA)
 void post_log_extra(u32 value);
@@ -93,6 +94,11 @@ int do_printk(int msg_level, const char *fmt, ...)
 
 int do_vprintk(int msg_level, const char *fmt, va_list args);
 
+#else
+
+static inline void romcc_printk(void) { }
+#define printk(...) romcc_printk()
+
 #endif /* !__ROMCC__ */
 
 #endif /* CONSOLE_CONSOLE_H_ */