ice: use bitmap_free instead of devm_kfree

pf->avail_txqs was allocated using bitmap_zalloc, bitmap_free should be
used to free this memory.

Fixes: 78b5713a

 ("ice: Alloc queue management bitmaps and arrays dynamically")
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>