bsp: qemu-virt64-riscv: remove config RISCV_S_MODE #4928

Job	Run time
RT-Thread Online Packages (STM32F407 RT-Spark)	8m 14s
RTduino/Arduino Libraries (STM32F412 Nucleo)	11m 22s
RTduino/Arduino Libraries (Raspberry Pico)	12m 24s
others_at32_hc32_ht32	6m 31s
stm32l4_f0_f1	13m 9s
stm32_f2_f4	10m 49s
stm32_f7_g0_h7_mp15_u5_h5_wb5	5m 57s
nxp_renesas	5m 44s
nuvoton	5m 41s
gd32_n32_apm32	5m 19s
Infineon_TI_microchip	7m 24s
mips	3m 13s
aarch64	4m 29s
riscv-none	2m 47s
riscv64-unknown	3m 54s
hpmicro	2m 44s
llvm-arm	6m 47s
simulator	2m 47s
ESP32C3	23m 9s
i386-unknown	3m 41s
nordic(yml)	11m 6s
	2h 37m 11s

Provide feedback