GPIO fixes for the v5.1 series:

- Revert the extended use of gpio_set_config() and think about
  how we can do this properly.

- Fix up the SPI CS GPIO handling so it now works properly on
  the SPI bus children, as intended.

- Error paths and driver fixes.
Merge tag 'gpio-v5.1-rc3-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into fixes

gpio fixes for v5.1-rc3

- fix for a potential NULL-pointer dereference in the aspeed driver
- revert of the commit using the new gpio_set_config() when setting
  debaunce and transitory state config as it caused a regression in
  the aspeed driver
- two fixes for gpio-mockup for debugfs problems introduced in the
  last merge window