USB: xhci: fix lots of compiler warnings.

Turns out someone never built this code on a 64bit platform.

Someone owes me a beer...

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>