Keep 'fscrypt' as key desc prefix, for compatibility with third party tools.

--- a/libcfs/include/uapi/linux/llcrypt.h
+++ b/libcfs/include/uapi/linux/llcrypt.h
@@ -48,7 +48,7 @@ struct llcrypt_policy_v1 {
  * Process-subscribed "logon" key description prefix and payload format.
  * Deprecated; prefer LL_IOC_ADD_ENCRYPTION_KEY instead.
  */
-#define LLCRYPT_KEY_DESC_PREFIX		"llcrypt:"
+#define LLCRYPT_KEY_DESC_PREFIX		"fscrypt:"
 #define LLCRYPT_KEY_DESC_PREFIX_SIZE	8
 #define LLCRYPT_MAX_KEY_SIZE		64
 struct llcrypt_key {
--- a/libcfs/libcfs/crypto/hkdf.c
+++ b/libcfs/libcfs/crypto/hkdf.c
@@ -129,7 +129,7 @@ int llcrypt_hkdf_expand(struct llcrypt_h
 
 	desc->tfm = hkdf->hmac_tfm;
 
-	memcpy(prefix, "llcrypt\0", 8);
+	memcpy(prefix, "fscrypt\0", 8);
 	prefix[8] = context;
 
 	for (i = 0; i < okmlen; i += HKDF_HASHLEN) {