xhci: Add missing unlocks on error paths

This patch adds missing unlocks on error paths in the
xhci_free_streams and xhci_configure_endpoint functions.

Signed-off-by: Emil Goode <emilgoode@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>