pci: Set err to errp directly rather than through error_propagate()

pci: Set err to errp directly rather than through error_propagate()

ioh3420_interrupts_init() pass error message to local_err, then
propagate it to errp by error_propagate(), which is not necessary.
So eliminate it and pass errp directly instead of local_err.

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>