dts: arm: st: h7: add st,stm32-qdec child nodes (disabled) Add st,stm32-qdec child nodes (disabled) under TIM nodes in STM32H7 DTSI files. Nodes are disabled by default; boards may enable them via overlays. No functional change. Signed-off-by: Ritesh Kudkelwar <ritesh.kumar0793@gmail.com>