RDMA/cxgb4: Use bitmap_zalloc() when applicable

Use 'bitmap_zalloc()' to simplify code, improve the semantic and avoid
some open-coded arithmetic in allocator arguments.

Using the 'zalloc' version of the allocator also saves a now useless
'bitmap_zero()' call.

Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
consistency.

While at it, remove an extra space in a statement just a few lines above.

Link: https://lore.kernel.org/r/e396c4aa16cd8945d43877570a8f6d926cea555a.1637789139.git.christophe.jaillet@wanadoo.frSigned-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/cxgb4/id_table.c

@@ -90,14 +90,12 @@ int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num,
 		alloc->last = prandom_u32() % RANDOM_SKIP;
 	else
 		alloc->last = 0;
-	alloc->max  = num;
+	alloc->max = num;
 	spin_lock_init(&alloc->lock);
-	alloc->table = kmalloc_array(BITS_TO_LONGS(num), sizeof(long),
-				     GFP_KERNEL);
+	alloc->table = bitmap_zalloc(num, GFP_KERNEL);
 	if (!alloc->table)
 		return -ENOMEM;
 
-	bitmap_zero(alloc->table, num);
 	if (!(alloc->flags & C4IW_ID_TABLE_F_EMPTY))
 		for (i = 0; i < reserved; ++i)
 			set_bit(i, alloc->table);
@@ -107,5 +105,5 @@ int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num,
 
 void c4iw_id_table_free(struct c4iw_id_table *alloc)
 {
-	kfree(alloc->table);
+	bitmap_free(alloc->table);
 }