[components][libc][compilers][common]移除time.c中未使用的变量timezone

components/libc/compilers/common/time.c

@@ -30,7 +30,6 @@ const short __spm[13] =
     (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30),
     (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31),
 };
-static long int timezone;
 static const char days[] = "Sun Mon Tue Wed Thu Fri Sat ";
 static const char months[] = "Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ";