LZ4_decompress_safe_forceExtDict() is only used in
lib/lz4/lz4_decompress.c, make it static to fix the
build warning about "no previous prototype" [1].

[1] https://lore.kernel.org/lkml/202206260948.akgsho1q-lkp@intel.com/

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 lib/lz4/lz4_decompress.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index fd1728d..59fe69a 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -507,9 +507,9 @@ static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest,
 				      (BYTE *)dest - prefixSize, NULL, 0);
 }
 
-int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
-				     int compressedSize, int maxOutputSize,
-				     const void *dictStart, size_t dictSize)
+static int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
+					    int compressedSize, int maxOutputSize,
+					    const void *dictStart, size_t dictSize)
 {
 	return LZ4_decompress_generic(source, dest,
 				      compressedSize, maxOutputSize,
-- 
2.1.0