Fix sscanf character conversion (%c): do not add '\0' at the end as for strings, cause, for example, parsing one character will fill two bytes: character itself and zero one '\0' after it, so will overflow one byte variable argument and corrupt memory for variables allocated after it.

libc/stdio/lib_sscanf.c

@@ -574,7 +574,6 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
                   if (!noassign)
                     {
                       strncpy(tv, buf, width);
-                      tv[width] = '\0';
                       count++;
                     }