ice: Optimize a few bitmap operations

When a bitmap is local to a function, it is safe to use the non-atomic
__[set|clear]_bit(). No concurrent accesses can occur.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>