usb: gadget: at91_udc: Fix clock names

usb: gadget: at91_udc: Fix clock names

The driver is requesting clock by their global name (those declared in the
clk_lookup list), but this only works with !CCF kernels.

Now that all SoCs have moved to CCF, fix the driver to use local names
(hclk and pclk).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>