tracing: convert irq trace points to new macros

Impact: enhancement

Converted the two irq trace point macros. The entry macro copies
the name of the irq handler, thus it is better to simply use the
TRACE_FORMAT macro which uses the trace_printk.

The return of the handler does not need to record the name, thus
the faster C style handler is more approriate.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>