Add assertion to dsl_dataset_set_compression_sync

Coverity pointed out that if we somehow receive SPA_FEATURE_NONE, we
will use a negative number as an array index. A defensive assertion
seems appropriate.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes openzfs#13872

module/zfs/dsl_dataset.c

@@ -4519,6 +4519,7 @@ dsl_dataset_set_compression_sync(void *arg, dmu_tx_t *tx)
 
 	uint64_t compval = ZIO_COMPRESS_ALGO(ddsca->ddsca_value);
 	spa_feature_t f = zio_compress_to_feature(compval);
+	ASSERT3S(f, !=, SPA_FEATURE_NONE);
 	ASSERT3S(spa_feature_table[f].fi_type, ==, ZFEATURE_TYPE_BOOLEAN);
 
 	VERIFY0(dsl_dataset_hold(dp, ddsca->ddsca_name, FTAG, &ds));