This patch ensures that the TWIHS (i2c) hw get's its clock set when the sequence of

sam_i2cbus_initialize
sam_i2cbus_uninitialize
sam_i2cbus_initialize

Or twi_reset is called.

I found this a while back in the stm32 family, so there may be more arch-es with this sort of bug. I suppose any driver that has the notion of "do not set the freq if it is already set" could be suspect.