module: s390: keep mod_arch_specific for livepatch modules

Livepatch needs to utilize the symbol information contained in the
mod_arch_specific struct in order to be able to call the s390
apply_relocate_add() function to apply relocations. Keep a reference to
syminfo if the module is a livepatch module. Remove the redundant vfree()
in module_finalize() since module_arch_freeing_init() (which also frees
those structures) is called in do_init_module(). If the module isn't a
livepatch module, we free the structures in module_arch_freeing_init() as
usual.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>