Fix for HPPA.

* configure.ac (HAVE_GCC_ATTRIBUTE_ALIGNED): Revert.
* src/gen-posix-lock-obj.c (USE_16BYTE_ALIGNMENT): Revert.
* src/syscfg/lock-obj-pub.hppa-unknown-linux-gnu.h: Revert.

This fixes commit 5168b97. I considered wrongly that long double were
128-bit in HPPA. Currently, all that we can do for HPPA is assuming
GCC and use its extension of "aligned" attribute.

• Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>