doc: board: phytec: phycore-am64: Fix phyBOARD Name

The Carrier-Board for the pyhCORE-AM64x is called phyBOARD-Electra.

Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
diff --git a/doc/board/phytec/phycore-am64x.rst b/doc/board/phytec/phycore-am64x.rst
index c99d8f6..ad9f47d 100644
--- a/doc/board/phytec/phycore-am64x.rst
+++ b/doc/board/phytec/phycore-am64x.rst
@@ -9,7 +9,7 @@
 with different carrier boards. This module can come with different sizes and
 models for DDR, eMMC, SPI NOR Flash and various SoCs from the AM64x family.
 
-A development Kit, called `phyBOARD-Lyra <https://www.phytec.com/product/phyboard-am64x>`_
+A development Kit, called `phyBOARD-Electra <https://www.phytec.com/product/phyboard-am64x>`_
 is used as a carrier board reference design around the AM64x SoM.
 
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