powerpc/44x: PHY fixup for USB on canyonlands board

This fix is a reset for USB PHY that requires some amount of time for power
to be stable on Canyonlands.

Signed-off-by: Rupjyoti Sarmah <rsarmah@apm.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>