Xen: drop exports of {set,clear}_foreign_p2m_mapping()

They're only used internally, and the layering violation they contain
(x86) or imply (Arm) of calling HYPERVISOR_grant_table_op() strongly
advise against any (uncontrolled) use from a module. The functions also
never had users except the ones from drivers/xen/grant-table.c forever
since their introduction in 3.15.

Signed-off-by: Jan Beulich <[e-mail]>
Reviewed-by: Stefano Stabellini <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Boris Ostrovsky <[e-mail]>

arch/arm/xen/p2m.c

···
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
 
 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 			      struct gnttab_unmap_grant_ref *kunmap_ops,
···
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
 
 bool __set_phys_to_machine_multi(unsigned long pfn,
 		unsigned long mfn, unsigned long nr_pages)

arch/x86/xen/p2m.c

···
 out:
 	return ret;
 }
-EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
 
 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 			      struct gnttab_unmap_grant_ref *kunmap_ops,
···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
 
 #ifdef CONFIG_XEN_DEBUG_FS
 #include <linux/debugfs.h>