libebl: Allow SHT_NOTE as relocation target type.

libebl: Allow SHT_NOTE as relocation target type.

eu-elflint uses ebl_check_reloc_target_type to determine whether a section
is a valid relocation target. In Fedora rawhide there are new ELF notes
(annobin) which have relocations against them in ET_REL files. eu-elflint
currently flags these as invalid. It looks like that is not correct.
I cannot find any reason an SHT_NOTE section cannot have relocations
against it. So this patch allows them.

Signed-off-by: Mark Wielaard <mark@klomp.org>