pinctrl: db8500: Fix some old bugs

pinctrl: db8500: Fix some old bugs

The Hulk robot reports these build warnings:

drivers/pinctrl/nomadik/pinctrl-nomadik-db8500.c:899:20: warning:
‘sbag_groups’ defined but not used [-Wunused-const-variable=]
 DB8500_FUNC_GROUPS(sbag, "sbag_oc2_1", "sbag_oc4_1");
                    ^
drivers/pinctrl/nomadik/pinctrl-nomadik-db8500.c:570:23: warning:
‘ipgpio6_c_2_pins’ defined but not used [-Wunused-const-variable=]
 static const unsigned ipgpio6_c_2_pins[] = { DB8500_PIN_G3 };
                       ^~~~~~~~~~~~~~~~
drivers/pinctrl/nomadik/pinctrl-nomadik-db8500.c:472:23: warning:
‘mc1dir_a_1_pins’ defined but not used [-Wunused-const-variable=]
 static const unsigned mc1dir_a_1_pins[] = { DB8500_PIN_AH13,
DB8500_PIN_AG12,
                       ^~~~~~~~~~~~~~~
drivers/pinctrl/nomadik/pinctrl-nomadik-db8500.c:453:23: warning:
‘modem_a_1_pins’ defined but not used [-Wunused-const-variable=]
 static const unsigned modem_a_1_pins[] = { DB8500_PIN_D22,
DB8500_PIN_C23,
                       ^~~~~~~~~~~~~~
drivers/pinctrl/nomadik/pinctrl-nomadik-db8500.c:430:23: warning:
‘kpskaskb_a_1_pins’ defined but not used [-Wunused-const-variable=]
 static const unsigned kpskaskb_a_1_pins[] = { DB8500_PIN_D17,
DB8500_PIN_D16 };
                       ^~~~~~~~~~~~~~~~~

They are just very old bugs in seldomly used pin groups.
Fix the problem by using the pins and referencing the
function.

Reported-by: Hulk Robot <hulkci@huawei.com>
Reported-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>