pinctrl: exynos: Remove eint_gpio_init call-back for exynos7 alive pinctrl block

The alive pin controller on exynos7 does not support external gpio
interrupts. Hence, remove the eint_gpio_init call-back for it. This
fixes the following error message seen during exynos7 boot-up:
"samsung-pinctrl 10580000.pinctrl: irq number not available"

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>