add kernel 5.3 support

[olegbuevich]

based on aircrack-ng/rtl8812au

[jerryzj]

This patch works on me.
Environment

OS: Fedora release 31 (Thirty One) x86_64
Kernel: 5.3.7-301.fc31.x86_64

Thanks

[jjsarton]

This patch works for me.
Fedora 30, 5.3.6-200.fc30.x86_64

[yuvalevr]

This patch works for me.
OS: Ubuntu 19.10
Kernel: 5.3.0-19-generic

[HelgeS]

This patch works for me.
OS: Arch Linux
Kernel: 5.3.10-arch1-1
Using this PKGBUILD: https://aur.archlinux.org/packages/rtl8814au-dkms-git with modified source

[AceStructor]

This patch works for me.
OS: Linux Mint 19.2
Kernel: 5.3.6-050306-generic

[ricardoper]

Works for me.

OS: Ubuntu 18.04 LTS
Kernel: 5.3.0-28-generic

Thanks.

[t206]

This patch works for me.

OS: Ubuntu 19.10 x86-64
Kernel: 5.3.0-29-generic

[nondescriptpointer]

Working for me too. Thanks a lot.
OS: Arch Linux
Kernel: 5.6.12-arch1-1