[Ada] Cleanup references to LynuxWorks in docs and comments

[Ada] Cleanup references to LynuxWorks in docs and comments

Apparently the company behind LynxOS is now called Lynx Software
Technologies (formerly LynuxWorks).

Use the current name in user docs and the previous name in developer
comment (to hopefully reflect the company name at the time when the
patchset mentioned in the comment was released).

2019-07-01  Piotr Trojanek  <trojanek@adacore.com>

gcc/ada/

	* sysdep.c: Cleanup references to LynuxWorks in docs and
	comments.

From-SVN: r272874