Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index d23c503..c289551 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -54,6 +54,9 @@
 int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 		unsigned int flags, const char *only);
 
+int string_escape_mem_ascii(const char *src, size_t isz, char *dst,
+					size_t osz);
+
 static inline int string_escape_mem_any_np(const char *src, size_t isz,
 		char *dst, size_t osz, const char *only)
 {