add new LED key systick sample code

guowenxue

2018-05-16 a22d9c106276bb1819e583012d7ea41b6529b318

 src/bare_test/2.Key/stdlib/inc/misc.h

copy from src/bare_test/stm32_key/fwlib/inc/misc.h
copy to src/bare_test/2.Key/stdlib/inc/misc.h