cpupower: Remove spurious return statement

print_duration() has a return; statement at the end of the function
that is not necessary as it's a void function.

Link: https://lore.kernel.org/r/20241218191144.3440854-2-superm1@kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/power/cpupower/utils/cpufreq-info.c

@@ -120,7 +120,6 @@ static void print_duration(unsigned long duration)
 		} else
 			printf("%lu ns", duration);
 	}
-	return;
 }
 
 static int get_boost_mode_x86(unsigned int cpu)