usb: host: ehci-msm: Remove dependency on OTG PHY

Currently the EHCI MSM driver has a hard dependency to be created
by an OTG layer, namely the phy-msm-usb driver. In some cases or
board configurations we want to allow the EHCI host to be
instantiated without OTG capability. Instead, relax the dependency
on having an OTG PHY being present and call usb_add_hcd() directly.

Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Timur Tabi <timur@codeaurora.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>