s390/vdso: Use common STABS_DEBUG and DWARF_DEBUG macros

s390/vdso: Use common STABS_DEBUG and DWARF_DEBUG macros

This simplifies the vDSO linker script.  The ELF_DETAILS macro was not
used in addition, as done on arm64 and powerpc, as that would introduce
an empty .modinfo section.

Note that this rearranges the .comment section to follow after all of
the debug sections.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>