pinctrl: cherryview: Add missing spinlock usage in chv_gpio_irq_handler

According to Braswell NDA Specification Update (#557593),
concurrent read accesses may result in returning 0xffffffff and write
instructions may be dropped. We have an established format for the
commit references, i.e.
cdca06e4 ("pinctrl: baytrail: Add missing spinlock usage in
byt_gpio_irq_handler")

Fixes: 0bd50d71 ("pinctrl: cherryview: prevent concurrent access to GPIO controllers")
Signed-off-by: Grace Kao <grace.kao@intel.com>
Reported-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>