linux_testing: 6.14-rc1 -> 6.14-rc2

pkgs/os-specific/linux/kernel/kernels-org.json

···
 {
     "testing": {
-        "version": "6.14-rc1",
-        "hash": "sha256:0schcgij7kdzj0zb6g3sjf32mq7s388hysrfzjzi5g1y3py21igk"
+        "version": "6.14-rc2",
+        "hash": "sha256:1i7zxjz0vckl31cb6anb0b9m0k7l3y2gk6r5y6in41p8mjf4rrpk"
     },
     "6.1": {
         "version": "6.1.128",