device: fix casting pointer to enum for sriov_reset_on_deactivate_cb()

Avoids a compiler warning:

    ../src/devices/nm-device.c:16079:26: error: cast to smaller integer type 'NMDeviceStateReason' from 'gpointer' (aka 'void *') [-Werror,-Wvoid-pointer-to-enum-cast]
            deactivate_ready (self, (NMDeviceStateReason) reason);
                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 121c58f0 ('core: set number of SR-IOV VFs asynchronously')
(cherry picked from commit 918ebd60)
(cherry picked from commit 32641b9f)
(cherry picked from commit c24888be)
20 jobs for nm-1-22 in 39 minutes and 42 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #4304550
checkpatch

00:01:16

manual #4304557
allowed to fail manual
t_centos:7.5.1804
manual #4304558
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t_centos:7.6.1810
manual #4304559
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t_centos:7.7.1908
manual #4304560
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t_centos:7.8.2003
manual #4304561
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t_centos:8.1.1911
manual #4304567
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t_debian:10
manual #4304566
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t_debian:9
manual #4304569
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t_debian:sid
manual #4304568
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t_debian:testing
manual #4304551
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t_fedora:28
manual #4304552
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t_fedora:29
manual #4304553
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t_fedora:30
passed #4304554
t_fedora:31

00:39:41

manual #4304555
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t_fedora:32
manual #4304556
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t_fedora:rawhide
manual #4304562
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t_ubuntu:16.04
manual #4304563
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t_ubuntu:18.04
manual #4304565
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t_ubuntu:devel
manual #4304564
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t_ubuntu:rolling