i386: Uglify some local identifiers in *intrin.h [PR107748]

i386: Uglify some local identifiers in *intrin.h [PR107748]

While reporting PR107748 (where is a problem with non-uglified names,
but I've left it out because it needs fixing anyway), I've noticed
various spots where identifiers in *intrin.h headers weren't uglified.
The following patch fixed those that are related to unions (I've grepped
for [a-zA-Z]\.[a-zA-Z] spots).
The reason we need those to be uglified is the same as why the arguments
of the inlines are __ prefixed and most of automatic vars in the inlines
- say a, v or u aren't part of implementation namespace and so users could
 #define u whatever->something
 #include <x86intrin.h>
and it should still work, as long as u is not e.g. one of the names
of the functions/macros the header provides (_mm* etc.).

2022-11-21  Jakub Jelinek  <jakub@redhat.com>

	PR target/107748
	* config/i386/avx512fp16intrin.h (_mm512_castph512_ph128,
	_mm512_castph512_ph256, _mm512_castph128_ph512,
	_mm512_castph256_ph512, _mm512_set1_pch): Uglify names of local
	variables and union members.
	* config/i386/avx512fp16vlintrin.h (_mm256_castph256_ph128,
	_mm256_castph128_ph256, _mm256_set1_pch, _mm_set1_pch): Likewise.
	* config/i386/smmintrin.h (_mm_extract_ps): Likewise.
	* config/i386/avx512bf16intrin.h (_mm_cvtsbh_ss): Likewise.

(cherry picked from commit ec8ec09f9414be871e322fecf4ebf53e3687bd22)