Re-enable chipidea irq even if there's no role changing to do. This is
a problem since b183c19f ("USB: chipidea: re-order irq handling to avoid
unhandled irqs"); when it manifests, chipidea irq gets disabled for good.

Cc: stable@vger.kernel.org # v3.7
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>