xen/grant-table: guard gnttab_suspend/resume with CONFIG_HIBERNATE_CALLBACKS

xen/grant-table: guard gnttab_suspend/resume with CONFIG_HIBERNATE_CALLBACKS

In current linux.git, gnttab_suspend() and gnttab_resume() are defined
and declared unconditionally. However, their only in-tree callers reside
in drivers/xen/manage.c, which are guarded by CONFIG_HIBERNATE_CALLBACKS.

Match the helper scope to their callers by wrapping the definitions in
CONFIG_HIBERNATE_CALLBACKS and providing no-op stubs in the header. This
fixes the config-scope mismatch and reduces the code footprint when
hibernation callbacks are disabled.

Signed-off-by: Pengpeng Hou <pengpeng.hou@isrc.iscas.ac.cn>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20260310080800.742223-1-pengpeng.hou@isrc.iscas.ac.cn>