arm64/neon: add workaround for ambiguous C99 stdint.h types

In a way similar to ARM commit 09096f6a ("ARM: 7822/1: add workaround
for ambiguous C99 stdint.h types"), this patch redefines the macros that
are used in stdint.h so its definitions of uint64_t and int64_t are
compatible with those of the kernel.

This patch comes from: https://patchwork.kernel.org/patch/3540001/
Wrote by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

We mark this file as a private file and don't have to override asm/types.h
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/neon-intrinsics.h

+/*
+ * Copyright (C) 2018 Linaro, Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ASM_NEON_INTRINSICS_H
+#define __ASM_NEON_INTRINSICS_H
+
+#include <asm-generic/int-ll64.h>
+
+/*
+ * In the kernel, u64/s64 are [un]signed long long, not [un]signed long.
+ * So by redefining these macros to the former, we can force gcc-stdint.h
+ * to define uint64_t / in64_t in a compatible manner.
+ */
+
+#ifdef __INT64_TYPE__
+#undef __INT64_TYPE__
+#define __INT64_TYPE__		long long
+#endif
+
+#ifdef __UINT64_TYPE__
+#undef __UINT64_TYPE__
+#define __UINT64_TYPE__		unsigned long long
+#endif
+
+/*
+ * genksyms chokes on the ARM NEON instrinsics system header, but we
+ * don't export anything it defines anyway, so just disregard when
+ * genksyms execute.
+ */
+#ifndef __GENKSYMS__
+#include <arm_neon.h>
+#endif
+
+#endif /* __ASM_NEON_INTRINSICS_H */