riscv: qemu: imply CONFIG_RNG_RISCV_ZKR

The zkr ISA extension can be used to generate random numbers. Since RVA22
zkr is an optional ISA extension. It can be emulated by QEMU. Our RNG
driver detects if the extension is usable during driver binding. Let's
enable it by default on QEMU.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/board/emulation/qemu-riscv/Kconfig b/board/emulation/qemu-riscv/Kconfig
index 012ac14..134dbfd 100644
--- a/board/emulation/qemu-riscv/Kconfig
+++ b/board/emulation/qemu-riscv/Kconfig
@@ -62,6 +62,7 @@
 	imply VIDEO_SIMPLE
 	imply PCIE_ECAM_GENERIC
 	imply DM_RNG
+	imply RNG_RISCV_ZKR
 	imply DM_RTC
 	imply RTC_GOLDFISH
 	imply SCSI