USB: musb: omap2430: drop non-DT support

Drop support for non-DT systems, which hasn't been used by a mainline
kernel since commit 9080b8dc ("ARM: OMAP2+: Remove legacy usb-host.c
platform init code"). Specifically, since that commit usb_get_phy_dev()
have always returned -ENODEV when looking up a legacy phy, something
which in turn would have led to the init callback returning
-EPROBE_DEFER indefinitely.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>