iova: Remove magazine BUG_ON() checks

Two of the magazine helpers have BUG_ON() checks, as follows:
- iova_magazine_pop() - here we ensure that the mag is not empty. However
  we already ensure that in the only caller, __iova_rcache_get().
- iova_magazine_push() - here we ensure that the mag is not full. However
  we already ensure that in the only caller, __iova_rcache_insert().

As described, the two bug checks are pointless so drop them.

Signed-off-by: John Garry <john.garry@huawei.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/1662557681-145906-3-git-send-email-john.garry@huawei.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: John Garry

drivers/iommu/iova.c

@@ -694,8 +694,6 @@ static unsigned long iova_magazine_pop(struct iova_magazine *mag,
 	int i;
 	unsigned long pfn;
 
-	BUG_ON(iova_magazine_empty(mag));
-
 	/* Only fall back to the rbtree if we have no suitable pfns at all */
 	for (i = mag->size - 1; mag->pfns[i] > limit_pfn; i--)
 		if (i == 0)
@@ -710,8 +708,6 @@ static unsigned long iova_magazine_pop(struct iova_magazine *mag,
 
 static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
 {
-	BUG_ON(iova_magazine_full(mag));
-
 	mag->pfns[mag->size++] = pfn;
 }