qemu-check.exp: remove duplicate 'virt' keyword

Fixes 'make check' error introduced by commit 6f0c0eb9 ("qemu: Add
'-machine secure=on' to arguments").

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Victor Chong <victor.chong@linaro.org>
Reviewed-by: Pascal Brand <pascal.brand@linaro.org>

qemu-check.exp

@@ -39,7 +39,7 @@ log_user 0
 # Save guest console output to a file
 log_file -a -noappend "serial0.log"
 info "Starting QEMU..."
-spawn ../qemu/arm-softmmu/qemu-system-arm -nographic -monitor none -machine virt -machine secure=on virt -cpu cortex-a15 -m 1057 -serial stdio -serial file:serial1.log -bios $bios
+spawn ../qemu/arm-softmmu/qemu-system-arm -nographic -monitor none -machine virt -machine secure=on -cpu cortex-a15 -m 1057 -serial stdio -serial file:serial1.log -bios $bios
 expect {
 	"Kernel panic" {
 		info "!!! Kernel panic\n"