[nvptx] Use MAX, MIN, ROUND_UP macros

[nvptx] Use MAX, MIN, ROUND_UP macros

Use MAX, MIN, and ROUND_UP macros to simplify code.

Build and reg-tested on x86_64 with nvptx accelerator.

2018-12-19  Tom de Vries  <tdevries@suse.de>

	* config/nvptx/nvptx.c (nvptx_gen_shared_bcast, shared_prop_gen)
	(nvptx_goacc_expand_accel_var): Use MAX and ROUND_UP.
	(nvptx_assemble_value, nvptx_output_skip): Use MIN.
	(nvptx_shared_propagate, nvptx_single, nvptx_expand_shared_addr): Use
	MAX.

From-SVN: r267261