[XCore][docs] Fix XCore compiler writer documentation links.

Fix links to XMOS website. Add link for XS2 architecture.

Reviewed By: jryans

Differential Revision: https://reviews.llvm.org/D92019

Author: nigelp-xmos

llvm/docs/CompilerWriterInfo.rst

@@ -131,8 +131,9 @@ X86
 XCore
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-* `The XMOS XS1 Architecture (ISA) <https://www.xmos.com/en/download/public/The-XMOS-XS1-Architecture%28X7879A%29.pdf>`_
-* `Tools Development Guide (includes ABI) <https://www.xmos.com/download/public/Tools-Development-Guide%28X9114A%29.pdf>`_
+* `The XMOS XS1 Architecture (ISA) <https://www.xmos.ai/download/The-XMOS-XS1-Architecture%281.0%29.pdf>`_
+* `The XMOS XS2 Architecture (ISA) <https://www.xmos.ai/download/xCORE-200:-The-XMOS-XS2-Architecture-%28ISA%29%281.1%29.pdf>`_
+* `Tools Development Guide (includes ABI) <https://www.xmos.ai/download/Tools-Development-Guide%282.1%29.pdf>`_
 
 Hexagon
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