module/raid: fix scanbuild warning

The issue:
bdev_raid.c:1323:60: warning: Division by zero
        raid_bdev->strip_size = (raid_bdev->strip_size_kb * 1024) / blocklen;

Fix this by adding assert.

Change-Id: Ic83ee2f8f74bc1bd0bcd90b75c796b1b4c2491d9
Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/873
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Paul Luse <paul.e.luse@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

module/bdev/raid/bdev_raid.c

@@ -1323,6 +1323,7 @@ raid_bdev_configure(struct raid_bdev *raid_bdev)
 			return -EINVAL;
 		}
 	}
+	assert(blocklen > 0);
 
 	/* The strip_size_kb is read in from user in KB. Convert to blocks here for
 	 * internal use.