clk: starfive: Factor out common JH7100 and JH7110 code

clk: starfive: Factor out common JH7100 and JH7110 code

The clock control registers on the StarFive JH7100 and JH7110 work
identically, so factor out the code then drivers for the two SoCs
can share it without depending on each other. No functional change.

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