This removes the mmio_... function calls to set the multicast bit for
the PHY registers when overriding the write leveling values. These are
not needed since multicast is set by default when calling the
function, and it's also better not to leave the side effect of
disabling multicast when exiting the function.

Change-Id: I83e089a2a2d55268b3832f36724c3b2c4be81082
Signed-off-by: Derek Basehore <dbasehore@chromium.org>