This patch adds interrupt support for Liteon 501 chip.

Interrupt will be generated whenever ALS or proximity
data exceeds values given in upper and lower threshold
register settings.
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>