console: Simplify vtxprintf

We do not need ROMCC support here and using wrappers for
console_tx_byte we can simplify this code.

Change-Id: I7f3b5acdfd0bde1d832b16418339dd5e232627e7
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5334
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/include/console/console.h

@@ -75,6 +75,7 @@ static inline void do_putchar(unsigned char byte) {}
 
 int do_printk(int msg_level, const char *fmt, ...) __attribute__((format(printf, 2, 3)));
 void do_putchar(unsigned char byte);
+void wrap_putchar(unsigned char byte, void *data);
 
 #define printk(LEVEL, fmt, args...)				\
 	do {							\