Merge tag 'arm-soc/for-5.3/maintainers' of https://github.com/Broadcom/stblinux into arm/fixes

This pull request contains MAINTAINERS file updates for Broadcom SoCs
entries for 5.3, please pull the following:

- Florian adds the Broadcom internal mailing-list which has a patchwork
  instance behind for the BCM2835 and BCM53573 SoCs entries

* tag 'arm-soc/for-5.3/maintainers' of https://github.com/Broadcom/stblinux

:
  MAINTAINERS: BCM53573: Add internal Broadcom mailing list
  MAINTAINERS: BCM2835: Add internal Broadcom mailing list

Signed-off-by: Olof Johansson <olof@lixom.net>