ionic: remove WARN_ON to prevent panic_on_warn

Remove unnecessary early code development check and the WARN_ON
that it uses.  The irq alloc and free paths have long been
cleaned up and this check shouldn't have stuck around so long.

Fixes: 77ceb68e ("ionic: Add notifyq support")
Signed-off-by: Nitya Sunkad <nitya.sunkad@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>