spmi: Add del_controller functionality

The del_controller function is required to release any client device
resources as well as the debugfs entries.  This patch adds that
functionality.

Change-Id: I91c6b840acfe002f096570cbe1867b302c475e60
Signed-off-by: Kenneth Heitke <kheitke@codeaurora.org>
diff --git a/include/linux/spmi.h b/include/linux/spmi.h
index 25d937a..e8e932e 100644
--- a/include/linux/spmi.h
+++ b/include/linux/spmi.h
@@ -54,6 +54,7 @@
 struct spmi_controller {
 	struct device		dev;
 	unsigned int		nr;
+	struct completion	dev_released;
 	int		(*cmd)(struct spmi_controller *, u8 opcode, u8 sid);
 	int		(*read_cmd)(struct spmi_controller *,
 				u8 opcode, u8 sid, u16 addr, u8 bc, u8 *buf);