riscv: No need to relocate the dtb as it lies in the fixmap region

commit 1b50f956 upstream.

We used to access the dtb via its linear mapping address but now that the
dtb early mapping was moved in the fixmap region, we can keep using this
address since it is present in swapper_pg_dir, and remove the dtb
relocation.

Note that the relocation was wrong anyway since early_memremap() is
restricted to 256K whereas the maximum fdt size is 2MB.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230329081932.79831-4-alexghiti@rivosinc.com


Cc: stable@vger.kernel.org # 5.15.x
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>