SPI0 flash timing calibration register
| SPI_MEM_TIMING_CLK_ENA | The bit is used to enable timing adjust clock for all reading operations. |
| SPI_MEM_TIMING_CALI | The bit is used to enable timing auto-calibration for all reading operations. |
| SPI_MEM_EXTRA_DUMMY_CYCLELEN | add extra dummy spi clock cycle length for spi clock calibration. |
| SPI_MEM_DLL_TIMING_CALI | Set this bit to enable DLL for timing calibration in DDR mode when accessed to flash. |
| UPDATE | Set this bit to update delay mode, delay num and extra dummy in MSPI. |