[ELF] - Ignore -Map,-M and --cref options.

-M, --print-map Write map file on standard output
-Map MAPFILENAME Write map file
--cref	Output cross reference table

This is relative to PR30973.

Next FreeBSD ports were atm failing because of 
lack of -Map, -M and --cref:

sysutils/openipmi
emulators/adamem
devel/jwasm
net/pimd
devel/k8048
textproc/libcrm114
lang/micropython
net/mrouted
print/openprinting

After this patch all of them can be link fine.

llvm-svn: 286831