KVM: x86: make apic_accept_irq tracepoint more generic

Initially the tracepoint was added only to the APIC_DM_FIXED case,
also because it reported coalesced interrupts that only made sense
for that case.  However, the coalesced argument is not used anymore
and tracing other delivery modes is useful, so hoist the call out
of the switch statement.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>