mtd: spi: renesas: Add R8A779H0 V4M support

Support RPC SPI on R8A779H0 V4M SoC.

Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>