ltp: upgrade 20200930 -> 20210121

0001-ltp-pan-Use-long-long-int-to-print-time_t.patch
removed since it is included in 20210121

Signed-off-by: Wang Mingyu <wangmy@cn.fujitsu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>