configure RTC PAD16
| X32N_FUN_IE | input enable in work mode |
| X32N_SLP_OE | output enable in sleep mode |
| X32N_SLP_IE | input enable in sleep mode |
| X32N_SLP_SEL | 1: enable sleep mode during sleep,0: no sleep mode |
| X32N_FUN_SEL | function sel |
| X32N_MUX_SEL | 1: use RTC GPIO,0: use digital GPIO |
| X32N_RUE | RUE |
| X32N_RDE | RDE |
| X32N_DRV | DRV |