[rs6000] Consistently use '__vector' instead of 'vector'

[rs6000] Consistently use '__vector' instead of 'vector'

Revision r265535 committed changes that used 'vector' instead of the
preferred '__vector'.  There is a reason that '__vector' is preferred,
because it ensures no conflicts with C++ namespace.  Indeed,
gcc/config/rs6000/xmmintrin.h undefines it, leading to errors:

  gcc/include/xmmintrin.h:999:20: error: 'vector' undeclared (first use in this function); did you mean 'vec_or'?
  gcc/include/xmmintrin.h:999:20: note: each undeclared identifier is reported only once for each function it appears in
  gcc/include/xmmintrin.h:999:26: error: expected ')' before 'long'
  gcc/include/xmmintrin.h:999:37: error: expected ')' before 'result'

Also fixed a few whitespace issues.

[gcc]

2018-10-29  Paul A. Clarke  <pc@us.ibm.com>

	* gcc/config/rs6000/mmintrin.h (_mm_packs_pi16, _mm_packs_pi32,
	_mm_packs_pu16, _mm_unpackhi_pi8, _mm_unpacklo_pi8, _mm_add_pi8,
	_mm_add_pi16, _mm_add_pi32, _mm_sub_pi8, _mm_sub_pi16, _mm_sub_pi32,
	_mm_cmpgt_pi8, _mm_cmpeq_pi16, _mm_cmpgt_pi16, _mm_cmpeq_pi32,
	_mm_cmpgt_pi32, _mm_adds_pi8, _mm_adds_pi16, _mm_adds_pu8,
	_mm_adds_pu16, _mm_subs_pi8, _mm_subs_pi16, _mm_subs_pu8,
	_mm_subs_pu16, _mm_madd_pi16, _mm_mulhi_pi16, _mm_mullo_pi16,
	_mm_sll_pi16, _mm_sra_pi16, _mm_srl_pi16, _mm_set1_pi16, _mm_set1_pi8):
	Change 'vector' to '__vector'.
	* gcc/config/rs6000/xmmintrin.h (_mm_cvtps_pi32, _mm_cvttps_pi32,
	_mm_cvtps_pi16, _mm_cvtps_pi8, _mm_max_pi16, _mm_max_pu8, _mm_min_pi16,
	_mm_min_pu8, _mm_mulhi_pu16, _mm_shuffle_pi16, _mm_avg_pu8,
	_mm_avg_pu16): Likewise.  And, whitespace corrections.

From-SVN: r265601