xhci-ext-caps.c: Add property to disable Intel SW switch

In platforms like Cherrytrail, 'SW switch enable' bit
should not be enabled for role switch. This patch
adds a property to Intel USB Role Switch platform driver
to denote that SW switch should be disabled in
Cherrytrail devices.

Signed-off-by: Saranya Gopal <saranya.gopal@intel.com>
Signed-off-by: Balaji Manoharan <m.balaji@intel.com>
Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/1567079760-24822-1-git-send-email-saranya.gopal@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>