octeontx2-af: Use the bitmap API to allocate bitmaps

Use devm_bitmap_zalloc() instead of hand-writing it.

This also makes the comment "Allocate bitmap for 32 entry mcam" more
explicit because now 32 is really used in the allocation function, instead
of an obscure 'sizeof(long)'.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/24177a9ee7043259448b735263d9cfd6a70e89a4.1669378798.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Jakub Kicinski <kuba@kernel.org>