pinctrl: samsung: Drop unused label field in samsung_pin_ctrl struct

There is no code using it and in fact there are pin controller variants
that do not even have this field initialized in their init data. This
patch removes it completely.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>

diff --cc drivers/pinctrl/samsung/pinctrl-exynos.c
Simple merge

diff --cc drivers/pinctrl/samsung/pinctrl-s3c24xx.c
Simple merge

diff --cc drivers/pinctrl/samsung/pinctrl-s3c64xx.c
Simple merge

diff --cc drivers/pinctrl/samsung/pinctrl-samsung.h
Simple merge