powerpc: Update documentation of ISA versions for Power10

Update the CPU to ISA Version Mapping document to include Power10 and
ISA v3.1.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Make sure ISA reference is unique]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200827040556.1783-1-jniethe5@gmail.com

Documentation/powerpc/isa-versions.rst

@@ -7,6 +7,7 @@ Mapping of some CPU versions to relevant ISA versions.
 ========= ====================================================================
 CPU       Architecture version
 ========= ====================================================================
+Power10   Power ISA v3.1
 Power9    Power ISA v3.0B
 Power8    Power ISA v2.07
 Power7    Power ISA v2.06
@@ -32,6 +33,7 @@ Key Features
 ========== ==================
 CPU        VMX (aka. Altivec)
 ========== ==================
+Power10    Yes
 Power9     Yes
 Power8     Yes
 Power7     Yes
@@ -47,6 +49,7 @@ PPC970     Yes
 ========== ====
 CPU        VSX
 ========== ====
+Power10    Yes
 Power9     Yes
 Power8     Yes
 Power7     Yes
@@ -62,6 +65,7 @@ PPC970     No
 ========== ====================================
 CPU        Transactional Memory
 ========== ====================================
+Power10    No  (* see Power ISA v3.1, "Appendix A. Notes on the Removal of Transactional Memory from the Architecture")
 Power9     Yes (* see transactional_memory.txt)
 Power8     Yes
 Power7     No