SPI SWE: clear any pending boot-time interrupts in spi_init() Charger plug/unplug hw logic in the Iota ABB has no built-in debouncing, thus electrical contact bounce on the charging power connection interface produces a lot of charger plug/unplug interrupts. When we boot in charging mode (charging power present at boot time and is presumably the cause of Switch-ON), some bounce may occur between the initial Iota Switch-ON action and Calypso firmware booting. By clearing any accumulated ITSTATREG interrupts on boot, we prevent these pre-boot interrupts from generating charger plug/unplug events to FCHG, which would upset smooth from-boot charging.