elf_helper: skip SYS_INIT() "devices"

SYS_INIT instantiates a device struct, but this is really
just used to run some functions at boot, it does not correspond
to a device driver belonging to a subsystem. Don't put them in
the kernel object table.

These are easy to filter since they are all named with the
_SYS_NAME macro.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>