HBSD: Pull in proposed OpenZFS change

FreeBSD's amotine@ opened a pull request[0] with the patch in this
commit. This commit pulls in that GitHub PR.

[0]: openzfs/zfs#13513

Signed-off-by:	Shawn Webb <shawn.webb@hardenedbsd.org>

sys/contrib/openzfs/module/zfs/spa_log_spacemap.c

@@ -511,12 +511,6 @@ spa_log_summary_decrement_blkcount(spa_t *spa, uint64_t blocks_gone)
 		e->lse_txgcount--;
 	for (; e != NULL; e = list_head(&spa->spa_log_summary)) {
 		if (e->lse_blkcount > blocks_gone) {
-			/*
-			 * Assert that we stopped at an entry that is not
-			 * obsolete.
-			 */
-			ASSERT(e->lse_mscount != 0);
-
 			e->lse_blkcount -= blocks_gone;
 			blocks_gone = 0;
 			break;