backport commit ("31096c3e8b11 net: stmmac: don't attach interface until resume finishes") to linux-5.4-stable

[Macpaul Lin]

Hi reviewers,

I suggest to backport 
commit "31096c3e8b11 net: stmmac: don't attach interface until resume finishes"
to linux-5.4 stable tree.

This patch fix resume issue by deferring netif_device_attach().

However, the patch cannot be cherry-pick directly on to stable-5.4.
A slightly change to the origin patch is required.
I'd like to provide the modification to stable-5.4 if it is needed.

commit: 31096c3e8b1163c6e966bf4d1f36d8b699008f84
subject: net: stmmac: don't attach interface until resume finishes
kernel version to apply to: Linux-5.4

Sorry for that I've send a wrong commit hash which is in my working tree
previously.

Thanks.
Macpaul Lin