riscv: dts: allwinner: convert isa detection to new properties

riscv: dts: allwinner: convert isa detection to new properties

Convert the D1 devicetrees to use the new properties
"riscv,isa-base" & "riscv,isa-extensions".
For compatibility with other projects, "riscv,isa" remains.

Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231009-moonlight-gray-92debdc89f30@wendy
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>