Revert "Added exFAT kconfig and build it as module"

This reverts commit cfa1f7e9b76f6f1b20c9db3eb3905536859ea0ed.
Revert "drivers/Makefile: fix exfat driver path"

This reverts commit 6cee9c0ac0882d052c3f0f75d56d9c2016f14215.
Revert "drivers/exfat: add Samsung's open source exFat module version 1.2.4"

This reverts commit b220033c9c63a613578639244b8caa4f9438be91.