riscv: RISCV_NONSTANDARD_CACHE_OPS shouldn't depend on RISCV_DMA_NONCOHERENT

RISCV_NONSTANDARD_CACHE_OPS is also used for the pmem cache maintenance
helpers, which are built into the kernel unconditionally.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231018052654.50074-2-hch@lst.de


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>