[nvptx] Eliminate PTX_VECTOR_LENGTH

[nvptx] Eliminate PTX_VECTOR_LENGTH

Remove PTX_VECTOR_LENGTH and replace uses of it with PTX_DEFAULT_VECTOR_LENGTH,
PTX_MAX_VECTOR_LENGTH and PTX_WARP_SIZE.

2019-01-07  Tom de Vries  <tdevries@suse.de>

	* config/nvptx/nvptx.c (PTX_VECTOR_LENGTH): Remove.
	(PTX_DEFAULT_VECTOR_LENGTH, PTX_MAX_VECTOR_LENGTH): Define.
	(nvptx_goacc_validate_dims_1, nvptx_dim_limit)
	(nvptx_goacc_reduction_fini): Use PTX_DEFAULT_VECTOR_LENGTH,
	PTX_MAX_VECTOR_LENGTH and PTX_WARP_SIZE instead of PTX_VECTOR_LENGTH.

From-SVN: r267626