cifs: print smb3_fs_context::source when mounting

Print full device name (UNC + optional prefix) from @old_ctx->source
when printing info about mount.

Before patch

  mount.cifs //srv/share/dir /mnt -o ...
  dmesg
  ...
  CIFS: Attempting to mount \\srv\share

After patch

  mount.cifs //srv/share/dir /mnt -o ...
  dmesg
  ...
  CIFS: Attempting to mount //srv/share/dir

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsfs.c

@@ -874,14 +874,12 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
 	struct cifs_mnt_data mnt_data;
 	struct dentry *root;
 
-	/*
-	 * Prints in Kernel / CIFS log the attempted mount operation
-	 *	If CIFS_DEBUG && cifs_FYI
-	 */
-	if (cifsFYI)
-		cifs_dbg(FYI, "Devname: %s flags: %d\n", old_ctx->UNC, flags);
-	else
-		cifs_info("Attempting to mount %s\n", old_ctx->UNC);
+	if (cifsFYI) {
+		cifs_dbg(FYI, "%s: devname=%s flags=0x%x\n", __func__,
+			 old_ctx->source, flags);
+	} else {
+		cifs_info("Attempting to mount %s\n", old_ctx->source);
+	}
 
 	cifs_sb = kzalloc(sizeof(struct cifs_sb_info), GFP_KERNEL);
 	if (cifs_sb == NULL) {