Fix output of LD_SHOW_AUXV=1.

Starting with commit 1616d034
the output was corrupted on some platforms as _dl_procinfo
was called for every auxv entry and on some architectures like s390
all entries were represented as "AT_HWCAP".

This patch is removing the condition and let _dl_procinfo decide if
an entry is printed in a platform specific or generic way.
This patch also adjusts all _dl_procinfo implementations which assumed
that they are only called for AT_HWCAP or AT_HWCAP2. They are now just
returning a non-zero-value for entries which are not handled platform
specifc.

ChangeLog:

	* elf/dl-sysdep.c (_dl_show_auxv): Remove condition and always
	call _dl_procinfo.
	* sysdeps/unix/sysv/linux/s390/dl-procinfo.h (_dl_procinfo):
	Ignore types other than AT_HWCAP.
	* sysdeps/sparc/dl-procinfo.h (_dl_procinfo): Likewise.
	* sysdeps/unix/sysv/linux/i386/dl-procinfo.h (_dl_procinfo):
	Likewise.
	* sysdeps/powerpc/dl-procinfo.h (_dl_procinfo): Adjust comment
	in the case of falling back to generic output mechanism.
	* sysdeps/unix/sysv/linux/arm/dl-procinfo.h (_dl_procinfo):
	Likewise.

(cherry picked from commit 7c651308)

Conflicts:
	ChangeLog