riscv: Kconfig.errata: Drop dependency for MMU in ERRATA_ANDES_CMO config

Now that RISCV_DMA_NONCOHERENT conditionally selects DMA_DIRECT_REMAP
ie only if MMU is enabled, we no longer need the MMU dependency in
ERRATA_ANDES_CMO config.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230901105858.311745-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>