[S390] appldata_base: Remove module_exit function and modular stuff

arch/s390/Kconfig tells us that CONFIG_APPLDATA_BASE is bool and hence can
never be built modular.  Given this, defining appldata_exit() function is
pointless (and wasteful, actually).  Remove all that.

Previous patch annotated appldata_offline_cpu() as __cpuexit, but now with the
__exit function appldata_exit() gone, the only callsite that references it is
__cpuinit, so this function can also be __cpuinit, thereby saving space when
HOTPLUG_CPU=n.

Signed-off-by: Satyam Sharma <satyam@infradead.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>