platform/x86/intel/ifs: Remove image loading during init

IFS test image is unnecessarily loaded during driver initialization.
Drop image loading during ifs_init() and improve module load time. With
this change, user has to load one when starting the tests.

As a consequence, make ifs_sem static as it is only used within sysfs.c

Suggested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20221117035935.4136738-4-jithu.joseph@intel.com