mfd: sec-core: Remove duplicated device type from sec_pmic_dev

The device type was stored in sec_pmic_dev state container twice:
 - unsigned long type (initialized from of_device_id or i2c_device_id)
 - int device_type (initialized as above or from board files when there
   is no DTS)

The 'type' field was never used outside of probe so it can be safely
removed.

Change also the device_type in sec_pmic_dev and sec_platform_data to
unsigned long to avoid any casts.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>