arch/arm64/boot.c: Only return if condition is met

Fix up commit b3847e64 (program loading: add prog_run() function),
which misses the braces for the if statement, causing the function
also to return if a non-payload program should be run causing the rest
of the stages never to be run.

Change-Id: I04940b218ba71e82af769c8db574528f830d0cbb
Found-by: Coverity, CID 1293136: Control flow issues (NESTING_INDENT_MISMATCH)
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/9306
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@gmail.com>

src/arch/arm64/boot.c

@@ -68,9 +68,10 @@ void arch_prog_run(struct prog *prog)
 	void (*doit)(void *);
 	void *arg;
 
-	if (ENV_RAMSTAGE && prog->type == PROG_PAYLOAD)
+	if (ENV_RAMSTAGE && prog->type == PROG_PAYLOAD) {
 		run_payload(prog);
 		return;
+	}
 
 	doit = prog_entry(prog);
 	arg = prog_entry_arg(prog);