do not use typedef for struct ctl_table

The typedef for struct ctl_table was removed from the kernel in
commit e5eea0981a3840f3f39f43d2d00461c4c24018e7. This change to
eio_procfs.c works with kernel versions before and after the change.
fix errors due to changes in wait_on_bit_lock

The old wait_on_bit_lock was replaced by wait_on_bit_lock_action. We use
that on kernels >= 3.17.