[PATCH] nvme-keyring: add MODULE_LICENSE()

[Randy Dunlap]

When NVME_KEYRING=y (NVME_AUTH is not set), there is a modpost build
error:

ERROR: modpost: missing MODULE_LICENSE() in drivers/nvme/common/nvme-common.o

so add a MODULE_LICENSE() to keyring.c (copied from auth.c).

Fixes: 9d77eb527784 ("nvme-keyring: register '.nvme' keyring")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Keith Busch <kbusch@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: linux-nvme@xxxxxxxxxxxxxxxxxxx
---
 drivers/nvme/common/keyring.c |    2 ++
 1 file changed, 2 insertions(+)

diff -- a/drivers/nvme/common/keyring.c b/drivers/nvme/common/keyring.c
--- a/drivers/nvme/common/keyring.c
+++ b/drivers/nvme/common/keyring.c
@@ -180,3 +180,5 @@ void nvme_keyring_exit(void)
 	key_put(nvme_keyring);
 }
 EXPORT_SYMBOL_GPL(nvme_keyring_exit);
+
+MODULE_LICENSE("GPL v2");