pinctrl: Use of_node_name_eq for node name comparisons

Convert string compares of DT node names to use of_node_name_eq helper
instead. This removes direct access to the node name pointer.

Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>