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/080-remove_compiler_check.patch

@@ -1,8 +1,8 @@
---- a/include/linux/compiler-gcc4.h
-+++ b/include/linux/compiler-gcc4.h
-@@ -2,13 +2,6 @@
- #error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
- #endif
+--- a/include/linux/compiler-gcc.h
++++ b/include/linux/compiler-gcc.h
+@@ -146,13 +146,6 @@
+ 
+ #if GCC_VERSION >= 40000
  
 -/* GCC 4.1.[01] miscompiles __weak */
 -#ifdef __KERNEL__
@@ -12,5 +12,5 @@
 -#endif
 -
  #define __used			__attribute__((__used__))
- #define __must_check 		__attribute__((warn_unused_result))
- #define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
+ #define __compiler_offsetof(a, b)					\
+ 	__builtin_offsetof(a, b)