pinctrl: dt-bindings: samsung: Add Exynos7 specific pinctrl macro definitions

Exynos7 SoC pinctrl configurations are similar to existing Exynos4/5 except
for FSYS1 pinctrl drive strengths. So adding Exynos7 specific FSYS1 blocks
pinctrl driver strength related macros which will be used in Exynos7
DTSi files.

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>