debugfs: debugfs_create_file_size(): use IS_ERR to check for error

debugfs_create_file() returns encoded error so use IS_ERR for checking
return value.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Fixes: ff9fb72b ("debugfs: return error values, not NULL")
Cc: stable <stable@vger.kernel.org>
References: https://gitlab.freedesktop.org/drm/amd/-/issues/1686
Link: https://lore.kernel.org/r/20210902102917.2233-1-nirmoy.das@amd.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/debugfs/inode.c

@@ -528,7 +528,7 @@ void debugfs_create_file_size(const char *name, umode_t mode,
 {
 	struct dentry *de = debugfs_create_file(name, mode, parent, data, fops);
 
-	if (de)
+	if (!IS_ERR(de))
 		d_inode(de)->i_size = file_size;
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file_size);