atapi: call ide_set_irq before ide_transfer_start

atapi: call ide_set_irq before ide_transfer_start

The ATAPI_INT_REASON_IO interrupt is raised when I/O starts, but in the
AHCI case ide_set_irq was actually called at the end of a mutual recursion.
Move it early, with the side effect that ide_transfer_start becomes a tail
call in ide_atapi_cmd_reply_end.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180606190955.20845-7-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>