Make *printf() return "int" instead of "void"

Change the return type of the *printf() functions to the standard
"int"; no changes are needed but returning the already available
length count.

This will save a few additional strlen() calls later...

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/common.h b/include/common.h
index 8bca04f..48f6a1a 100644
--- a/include/common.h
+++ b/include/common.h
@@ -663,7 +663,7 @@
  * STDIO based functions (can always be used)
  */
 /* serial stuff */
-void	serial_printf (const char *fmt, ...)
+int	serial_printf (const char *fmt, ...)
 		__attribute__ ((format (__printf__, 1, 2)));
 /* stdin */
 int	getc(void);
@@ -672,9 +672,9 @@
 /* stdout */
 void	putc(const char c);
 void	puts(const char *s);
-void	printf(const char *fmt, ...)
+int	printf(const char *fmt, ...)
 		__attribute__ ((format (__printf__, 1, 2)));
-void	vprintf(const char *fmt, va_list args);
+int	vprintf(const char *fmt, va_list args);
 
 /* stderr */
 #define eputc(c)		fputc(stderr, c)
@@ -689,7 +689,7 @@
 #define stderr		2
 #define MAX_FILES	3
 
-void	fprintf(int file, const char *fmt, ...)
+int	fprintf(int file, const char *fmt, ...)
 		__attribute__ ((format (__printf__, 2, 3)));
 void	fputs(int file, const char *s);
 void	fputc(int file, const char c);