USB: EHCI: msm: Add support for HSIC based Host Controller

This patch adds support for EHCI compliant USB Host Controller
present in MSM chips. This Controller uses an HSIC PHY which
communicates with downstream devices using STROBE/DATA lines.

HSIC is a supplement to USB 2.0 specification and is preferred
for chip-to-chip interconnect (having maximum circuit length of
10cm) as it removes the analog transceivers.

Change-Id: Id54dcc802e606e0ff7dd31bc64671a797cd8bc09
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>