mpc85xx: powerpc: usb: Modified the erratum A006261 according to endianness

Modifies erratum implementation due to the fact that P3041,
P5020, and P5040 are all big endian for the USB PHY registers, but
they were specified little endian.

Signed-off-by: Sriram Dash <sriram.dash@nxp.com>
Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>