xhci: hsic: Convert host_ready into a module parameter

host_ready is created as a platform device sysfs file.
Userspace needs this file to persist across driver
unbind/bind, hence make it a driver module parameter.

Change-Id: Ib5c58ac215bc588842727f2329779a0ea1cc26dd
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>