eCryptfs: Fix min function comparison warning

This warning shows up on 64 bit builds:

fs/ecryptfs/inode.c:693: warning: comparison of distinct pointer types
lacks a cast

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 1940edd..2f0945d 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -690,7 +690,7 @@
 		}
 		/* Check for bufsiz <= 0 done in sys_readlinkat() */
 		rc = copy_to_user(buf, plaintext_name,
-				  min((unsigned) bufsiz, plaintext_name_size));
+				  min((size_t) bufsiz, plaintext_name_size));
 		if (rc)
 			rc = -EFAULT;
 		else