x86, perf: Use apic_write unconditionally

Since apic_write() maps to a plain noop in the !CONFIG_X86_LOCAL_APIC
case we're safe to remove this conditional compilation and clean up
the code a bit.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: fweisbec@gmail.com
Cc: acme@redhat.com
Cc: eranian@google.com
Cc: peterz@infradead.org
LKML-Reference: <20100317104356.232371479@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>