Fixed type conversion ambiguity

src/common/string_util.cpp

@@ -117,7 +117,7 @@ std::string StringFromFormat(const char* format, ...) {
 }
 
 // For Debugging. Read out an u8 array.
-std::string ArrayToString(const u8* data, u32 size, int line_len, bool spaces) {
+std::string ArrayToString(const u8* data, size_t size, int line_len, bool spaces) {
     std::ostringstream oss;
     oss << std::setfill('0') << std::hex;