Fix automake warnings

Fix automake warnings

Apparently, commit 2f02e81510946a4c8e9157ad0b72d92894b9acd7 that removed
$(EXEEXT) suffix from shared libraries was incomplete: it missed the
fact that some libraries were included into noinst_PROGRAMS, resulting
to the following automake warnings:

libasm/Makefile.am:66: warning: deprecated feature: target 'libasm.so' overrides 'libasm.so$(EXEEXT)'
libdw/Makefile.am:114: warning: deprecated feature: target 'libdw.so' overrides 'libdw.so$(EXEEXT)'
libelf/Makefile.am:116: warning: deprecated feature: target 'libelf.so' overrides 'libelf.so$(EXEEXT)'

Fix this by renaming noinst_PROGRAMS to noinst_DATA and removing no
longer needed lib{asm,dw,elf}_so_SOURCES variables and add lib{asm,dw,elf).so
to CLEANFILES.

Fixes: 2f02e8151094 ("Drop $(EXEEXT) suffix from shared libraries")
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Mark Wielaard <mark@klomp.org>