usb: Fix build error due to dma_mask is not at pdev_archdata at ARM

usb: Fix build error due to dma_mask is not at pdev_archdata at ARM

When build i.mx platform with imx_v6_v7_defconfig, and after adding
USB Gadget support, it has below build error:

CC      drivers/usb/host/fsl-mph-dr-of.o
drivers/usb/host/fsl-mph-dr-of.c: In function 'fsl_usb2_device_register':
drivers/usb/host/fsl-mph-dr-of.c:97: error: 'struct pdev_archdata'
has no member named 'dma_mask'

It has discussed at: http://www.spinics.net/lists/linux-usb/msg57302.html

For PowerPC, there is dma_mask at struct pdev_archdata, but there is
no dma_mask at struct pdev_archdata for ARM. The pdev_archdata is
related to specific platform, it should NOT be accessed by
cross platform drivers, like USB.

The code for pdev_archdata should be useless, as for PowerPC,
it has already gotten the value for pdev->dev.dma_mask at function
arch_setup_pdev_archdata of arch/powerpc/kernel/setup-common.c.

Tested-by: Ramneek Mehresh <ramneek.mehresh@freescale.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>