riscv: dts: starfive: Add StarFive JH7110 pin function definitions

Add pin function definitions for StarFive JH7110 SoC.

Tested-by: Tommaso Merciai <tomm.merciai@gmail.com>
Co-developed-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Jianlong Huang <jianlong.huang@starfivetech.com>
Signed-off-by: Hal Feng <hal.feng@starfivetech.com>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>