eventdev: fix possible use of uninitialized var

eventdev: fix possible use of uninitialized var

Fix the logic for the case of event queue allowing all schedule types.

Compiler warning pointing to this error (with LTO enabled):
error: ‘sched_type’ may be used uninitialized in this function
[-Werror=maybe-uninitialized]
  if ((ret < 0 && ret != -EOVERFLOW) ||

Fixes: 6750b21bd6af ("eventdev: add default software timer adapter")
Cc: stable@dpdk.org
Signed-off-by: Andrzej Ostruszka <aostruszka@marvell.com>
Reviewed-by: Jerin Jacob <jerinj@marvell.com>