Revert "Fix fs/gfs2/Kconfig from eradicate CONFIG_HOTPLUG commit"

This reverts commit b1fb331487ac4745765a1a3b90817d82124ae6c2.
Revert "Finally eradicate CONFIG_HOTPLUG"

This reverts commit 5fb5e86616ca45745699b2e0322023fee3b4e118.
Revert "CONFIG_HOTPLUG should be always on"

This reverts commit a7481a1483005459298e2bfa914f726bad6457af.