'unsigned int' is better suited as an array index on x86-64.

'u32' produces better code than 'unsigned long' on x86-64, so use the
former for storing 32-bit values read from the hardware.

this_cpu() uses an implicit smp_processor_id(), and hence using
per_cpu() when the result of smp_processor_id() is already available
is more efficient.

Fold one case of cpu_isset()+cpu_clear() into cpu_test_and_clear().

Drop the unused return value of evt_do_broadcast().

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Wei Gang <gang.wei@intel.com>