usb: remove msm_hsusb_hw.h

The last two remaining drivers (ehci-msm.c and phy-msm-usb.c) that
needed this header were recently removed, so delete this now-unused
file.

Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>