libpayload: Add missing SIZE_MAX define

commonlib/region.h requires SIZE_MAX to be defined.

Change-Id: I588d59c2637b10def046ea02293e5503c9b6bc3d
Signed-off-by: Jakub Czapiga <czapiga@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83907
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Eric Lai <ericllai@google.com>

payloads/libpayload/include/stdint.h

@@ -54,4 +54,12 @@ typedef long ptrdiff_t;
 #define UINT32_MAX	(4294967295U)
 #define UINT64_MAX	(18446744073709551615ULL)
 
+#ifndef SIZE_MAX
+#ifdef __SIZE_MAX__
+#define SIZE_MAX __SIZE_MAX__
+#else
+#define SIZE_MAX (~(size_t)0)
+#endif /* __SIZE_MAX__ */
+#endif /* SIZE_MAX */
+
 #endif