[bsp] Fix a typo in qemu.sh (#5612)

bsp/qemu-vexpress-a9/qemu.sh

@@ -2,4 +2,4 @@ if [ ! -f "sd.bin" ]; then
 dd if=/dev/zero of=sd.bin bs=1024 count=65536
 fi
 
-qemu-system-arm -M vexpress-a9 -smp cpus=2 -kernel rtthread.bin -serial stdio -sd sd.bin -show-curse
+qemu-system-arm -M vexpress-a9 -smp cpus=2 -kernel rtthread.bin -serial stdio -sd sd.bin -show-cursor