tools/mkimage: update to version 2018.03

This activates support for fit images and some other new mkimage
features. Some of the patches were applied upstream and could be
removed.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

tools/mkimage/patches/060-remove_kernel_includes.patch

@@ -1,6 +1,6 @@
 --- a/include/compiler.h
 +++ b/include/compiler.h
-@@ -58,6 +58,11 @@ typedef uint8_t __u8;
+@@ -66,6 +66,11 @@ typedef uint8_t __u8;
  typedef uint16_t __u16;
  typedef uint32_t __u32;
  typedef unsigned int uint;