smp: Remove superfluous cond_func check in smp_call_function_many_cond()

It was requested to remove the cond_func check but the follow up patch was
overlooked. Remove it now.

Fixes: 67719ef2 ("smp: Add a smp_cond_func_t argument to smp_call_function_many()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200127083915.434tdkztorkklpdu@linutronix.de