elf_reader: tolerate untyped/local map relocations from llvm 7/9
elf_reader: tolerate untyped/local map relocations from llvm 7/9

Symbols for anonymous constants are somewhat irregular on older versions
of LLVM. This commit relaxes the constraints on symbols those compilers
emit map relocations against.

LLVM 7:
     1: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT    16 .Lconstinit.1

LLVM 9:
     1: 0000000000000000    32 OBJECT  LOCAL  DEFAULT    22 .Lconstinit.1

LLVM 14 has these symbols correctly sanitized.

Signed-off-by: Timo Beckers <98c2d5a1e48c998bd9ba9dbc53d6857beae1c9bd@isovalent.com>

cilium/ebpf,cilium/ebpf