tiny-printf: Support %i

The most basic printf("%i", value) formating string was missing,
add it for the sake of convenience.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefan Roese <sr@denx.de>
diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c
index 1138c70..8fc7e48 100644
--- a/lib/tiny-printf.c
+++ b/lib/tiny-printf.c
@@ -242,6 +242,7 @@
 				goto abort;
 			case 'u':
 			case 'd':
+			case 'i':
 				div = 1000000000;
 				if (islong) {
 					num = va_arg(va, unsigned long);
@@ -251,7 +252,7 @@
 					num = va_arg(va, unsigned int);
 				}
 
-				if (ch == 'd') {
+				if (ch != 'u') {
 					if (islong && (long)num < 0) {
 						num = -(long)num;
 						out(info, '-');