lightnvm: fix out-of-bounds write to array devices->info[]

There is an off-by-one array check that can lead to a out-of-bounds
write to devices->info[i]. Fix this by checking by using >= rather
than > for the size check. Also replace hard-coded array size limit
with ARRAY_SIZE on the array.

Addresses-Coverity: ("Out-of-bounds write")
Fixes: cd9e9808d18f ("lightnvm: Support for Open-Channel SSDs")
Signed-off-by: Colin Ian King <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

drivers/lightnvm/core.c

···
 		strlcpy(info->bmname, "gennvm", sizeof(info->bmname));
 		i++;
 
-		if (i > 31) {
-			pr_err("max 31 devices can be reported.\n");
+		if (i >= ARRAY_SIZE(devices->info)) {
+			pr_err("max %zd devices can be reported.\n",
+			       ARRAY_SIZE(devices->info));
 			break;
 		}
 	}