[new uImage] Add sha1.o object to mkimage binary build

Signed-off-by: Bartlomiej Sieka <tur@semihalf.com>
diff --git a/tools/mkimage.h b/tools/mkimage.h
index 8b05bb1..a01977e 100644
--- a/tools/mkimage.h
+++ b/tools/mkimage.h
@@ -32,6 +32,7 @@
 #include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>
+#include <sha1.h>
 
 #if defined(__BEOS__) || defined(__NetBSD__) || defined(__APPLE__)
 #include <inttypes.h>