riscv: dts: starfive: Update flash partition layout

riscv: dts: starfive: Update flash partition layout

Up to now, the describe flash partition layout has some gaps.
Use the whole flash chip by getting rid of the gaps.

Suggested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>