fscrypt: remove redundant assignment of res

res is assigned to sizeof(ctx), however, this is unused and res
is updated later on without that assigned value to res ever being
used.  Remove this redundant assignment.

Fixes CoverityScan CID#1395546 "Unused value"
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

fs/crypto/keyinfo.c

@@ -211,7 +211,6 @@ int fscrypt_get_crypt_info(struct inode *inode)
 		ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
 		ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
 		memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
-		res = sizeof(ctx);
 	} else if (res != sizeof(ctx)) {
 		return -EINVAL;
 	}