i2c: designware move to using single isr

With ioapic_mkstub now taking a context value we can have a single isr
routine and move away from the isr trampolines we have now

Change-Id: Ibbb0f627ac515b12c0590a71da6a3267c952dd30
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>