mfd: intel_quark_i2c_gpio: Switch to use struct device *

There is no need to pass struct pci_dev * to intel_quark_register_i2c_clk() and
intel_quark_unregister_i2c_clk(). Change the parameter to struct device *. As a
result store it in the private struct instead of struct pci_dev *.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>