There are ulpi access ops implemented in drivers/usb/phy/phy-ulpi.c.
mxc access ops implement the same access operations within mach-imx. This
patch removes the mxc ulpi file and uses phy-ulpi instead for
imx_otg_ulpi_create.
phy-ulpi successfully tested with i.MX27 Phytec phyCARD-S (pca100).