USB: xhci: Fix compile issues with xhci_get_slot_state()

Randy Dunlap reported this error when compiling the xHCI driver:

linux-next-20100104/drivers/usb/host/xhci.h:1214:
sorry, unimplemented: inlining failed in call to 'xhci_get_slot_state': function body not available

The xhci_get_slot_state() function belongs in xhci-dbg.c, since it
involves debugging internal xHCI structures.  However, it is only used in
xhci-hcd.c.  Some toolchains may have issues since the inlined function
body is not in the xhci.h header file.  Remove the inline keyword to avoid
this.

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>