Add UINT32_MAX and UINT64_MAX

These constants are defined by stdint.h but not by kernel.h, which is
its stand-in in U-Boot. Add the definitions so that libraries which expect
stdint.h constants can work.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 04a09eb..bd88483 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -33,6 +33,10 @@
 #define S64_MAX		((s64)(U64_MAX>>1))
 #define S64_MIN		((s64)(-S64_MAX - 1))
 
+/* Aliases defined by stdint.h */
+#define UINT32_MAX	U32_MAX
+#define UINT64_MAX	U64_MAX
+
 #define STACK_MAGIC	0xdeadbeef
 
 #define REPEAT_BYTE(x)	((~0ul / 0xff) * (x))