ARM: dts: msm: remove extra pinctrl dtsi include from msm8998

msm8998-pintctrl dtsi is already included by msm8998.dtsi. So we don't
need to include this file in board specific dtsi.

Change-Id: Iee7c0f4b8bd7da40ff059c531a450a0f3d3b2ae7
Signed-off-by: Shashank Mittal <mittals@codeaurora.org>