usb: ehci-msm-hsic: Use old scheme of ehci-hcd (not as library)

HSIC HC driver uses has various intrusive overrides to ehci-hcd
driver for debugging and various hardware bugs. Also HBM requires
to override basic urb_queue routines. Until HSIC driver is modified
accordingly to use new ehci hcd as library scheme, keep using the
old legacy scheme of including ehci-msm-hsic platform driver from
ehci-hcd. Other two msm drivers: ehci-msm.c and ehci-msm2.c are
using new scheme, hence it is not required to add changes in
ehci-hcd.c to support multiple PLATFORM_DRIVERs.

Change-Id: Ife9002160919d57dc6fc550bb7b1b4317f28589a
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>