Use bitmap_zalloc()/bitmap_free() instead of hand-writing them.

It is less verbose and it improves the semantic.

Link: https://lore.kernel.org/r/1f671b1af5881723ee265a0a12809c92950e58aa.1657567269.git.christophe.jaillet@wanadoo.frSigned-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: NShiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: NLeon Romanovsky <leon@kernel.org>