Revert "kbuild/mkspec: support 'update-bootloader'-based systems"
This reverts commit 27c3bffd230abd0a598586aed0fe0ba7b61e0e2e.
If this is still needed, we can bring it back.
However, I'd like to understand why 'update-bootloader --remove' is
needed for uninstallation, while 'update-bootloader --add' was not
called during the installation.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>