vboot: Call verification_should_run directly in the if statement

Using a dedicated variable is slightly less readable and makes the code
less consistent, given that other test functions are called directly in
the if statements.

Change-Id: If52b2a4268acb1e2187574d15cc73a0c1d5fe9bb
Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-on: https://review.coreboot.org/14817
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

src/vendorcode/google/chromeos/vboot2/vboot_loader.c

@@ -88,11 +88,7 @@ static int vboot_logic_executed(void)
 
 static void vboot_prepare(void)
 {
-	int run_verification;
-
-	run_verification = verification_should_run();
-
-	if (run_verification) {
+	if (verification_should_run()) {
 		verstage_main();
 		car_set_var(vboot_executed, 1);
 	} else if (verstage_should_load()) {