riscv: dts: starfive: jh7110: Add syscon nodes

Add stg_syscon/sys_syscon/aon_syscon/PLL nodes for JH7110 SoC.

Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Co-developed-by: Xingyu Wu <xingyu.wu@starfivetech.com>
Signed-off-by: Xingyu Wu <xingyu.wu@starfivetech.com>
Signed-off-by: William Qiu <william.qiu@starfivetech.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>