spi: cadence-quadspi: Allow compilation on RISC-V

This IP is also used on the Starfive JH7100 riscv64 SoC and presumably
also the upcoming JH7110 SoC.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>

drivers/spi/Kconfig

@@ -219,7 +219,7 @@ config SPI_CADENCE
 
 config SPI_CADENCE_QUADSPI
  tristate "Cadence Quad SPI controller"
- depends on OF && (ARM || ARM64 || X86 || COMPILE_TEST)
+ depends on OF && (ARM || ARM64 || RISCV || X86 || COMPILE_TEST)
  help
  Enable support for the Cadence Quad SPI Flash controller.