pinctrl: cherryview: Remove unused groups of pins

For the long time no one complained about unused groups of pins
for fSPI and SMBUS.

Remove them for good and at the same time satisfy compiler,
otherwise get warning:

CC      drivers/pinctrl/intel/pinctrl-cherryview.o
drivers/pinctrl/intel/pinctrl-cherryview.c:285:23: warning: ‘southwest_smbus_pins’ defined but not used [-Wunused-const-variable=]
  static const unsigned southwest_smbus_pins[] = { 79, 81, 82 };
                        ^~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/intel/pinctrl-cherryview.c:269:23: warning: ‘southwest_fspi_pins’ defined but not used [-Wunused-const-variable=]
  static const unsigned southwest_fspi_pins[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
                        ^~~~~~~~~~~~~~~~~~~

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>