kernel: i2c: core: Run atomic i2c xfer when !preemptible

In the Linux kernel, the following vulnerability has been resolved: i2c: core: Run atomic i2c xfer when !preemptible Since bae1d3a05a8b, i2c transfers are non-atomic if preemption is disabled. However, non-atomic i2c transfers require preemption e.g. in waitforcompletion while waiting for the DMA...