mfd: intel_soc_pmic_bxtwc: Remove thermal second level IRQs

Since all second level thermal IRQs are consumed by the same
device(bxt_wcove_thermal), there is no need to expose them as separate
interrupts. We can just export only the first level IRQs for thermal and
let the device(bxt_wcove_thermal) driver handle the second level IRQs
based on thermal interrupt status register. Also, just using only the
first level IRQ will eliminate the bug involved in requesting only the
second level IRQ and not explicitly enable the first level IRQ. For
more info on this issue please read the details at,

https://lkml.org/lkml/2017/2/27/148



This patch also makes relevant change in bxt_wcove_thermal driver to use
only first level PMIC thermal IRQ.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>