board: ti: invoke clock API to enable and disable clocks

invoke enable_usb_clocks during board_usb_init and disable_usb_clocks
during board_usb_exit to enable and disable clocks respectively.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/board/ti/dra7xx/evm.c b/board/ti/dra7xx/evm.c
index eaf123c..890b603 100644
--- a/board/ti/dra7xx/evm.c
+++ b/board/ti/dra7xx/evm.c
@@ -163,6 +163,7 @@
 
 int board_usb_init(int index, enum usb_init_type init)
 {
+	enable_usb_clocks(index);
 	switch (index) {
 	case 0:
 		if (init == USB_INIT_DEVICE) {
@@ -209,6 +210,7 @@
 	default:
 		printf("Invalid Controller Index\n");
 	}
+	disable_usb_clocks(index);
 	return 0;
 }