mpi: Allow building with --disable-asm for HPPA.
* mpi/longlong.h [__hppa] (udiv_qrnnd): Only define when assembler is enabled.
Cherry-picked form master commit of:
c0692324fe8b3806eefc5017767917dca9cd94d0
- GnuPG-bug-id: T5976
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>