includes: move openssl headers to include/u-boot

commit 18b06652cd "tools: include u-boot version of sha256.h"
unconditionally forced the sha256.h from u-boot to be used
for tools instead of the host version. This is fragile though
as it will also include the host version. Therefore move it
to include/u-boot to join u-boot/md5.h etc which were renamed
for the same reason.

cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
diff --git a/tools/imagetool.h b/tools/imagetool.h
index c480687..c8af0e8 100644
--- a/tools/imagetool.h
+++ b/tools/imagetool.h
@@ -18,7 +18,7 @@
 #include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>
-#include <sha1.h>
+#include <u-boot/sha1.h>
 #include "fdt_host.h"
 
 #define ARRAY_SIZE(x)		(sizeof(x) / sizeof((x)[0]))