arch: rockchip: rk3588: Fix missing suffix 'A' for Edgeble Neu6A

Add missing suffix 'A' for Edgeble Neu6A SoM and IO boards.

Fixes: <15b2d1fb727> ("board: rockchip: Add Edgeble Neural Compute
Module 6")
Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/doc/board/rockchip/rockchip.rst b/doc/board/rockchip/rockchip.rst
index 4c555e1..315ad41 100644
--- a/doc/board/rockchip/rockchip.rst
+++ b/doc/board/rockchip/rockchip.rst
@@ -98,7 +98,7 @@
 
 * rk3588
      - Rockchip EVB (evb-rk3588)
-     - Edgeble Neural Compute Module 6 SoM - Neu6a (neu6a-io-rk3588)
+     - Edgeble Neural Compute Module 6A SoM - Neu6a (neu6a-io-rk3588)
      - Radxa ROCK 5B (rock5b-rk3588)
 
 * rv1108