lptmr CNR寄存器要先写值才能读到有效值
lptmr PTC5的ALT3功能才是LPTMR0_ALT2
PIT在200M的core clk下不是特别稳定，要在LPLD_PIT_Init()中重新开启PIT
add pit module
add encoder module
add motor module
modify LPLD_LPTMR_ResetCounter(): it will reset CNT and restart LPTMER again
app: add pit, encoder, motor func
Merge branch 'smartcar' of github.com:zjh3123629/smartcar into smartcar