arm64: dts: qcom: msm8916-samsung-a2015: Add touchscreen pinctrl

A3, A5 and most of the Samsung phones with MSM8916 SoC use GPIO pin 13 for
touchscreen interrupts. Add touchscreen pinctrl to a2015 common dtsi.

Signed-off-by: Lin, Meng-Bo <linmengbo0689@protonmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220610175332.104154-1-linmengbo0689@protonmail.com