IB/ehca: Remove _irqsave, move #ifdef

- In ehca_process_eq(), we're IRQ safe throughout the whole function, so we
  don't need another _irqsave in the middle of flight.

- take_over_work() is only called by comp_pool_callback(), so it can move
  into the same #ifdef block.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>