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/console/vsprintf.c

@@ -48,7 +48,7 @@ static int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 
 	ctx.str_buf = buf;
 	ctx.buf_limit = size ? size - 1 : 0;
-	i = vtxdprintf(str_tx_byte, fmt, args, &ctx);
+	i = vtxprintf(str_tx_byte, fmt, args, &ctx);
 	if (size)
 		*ctx.str_buf = '\0';