board/rde1edge: rename sgiclarkh to rde1edge

Replace all usage of 'sgiclark' with 'rdn1e1edge' and 'sgiclarkh' with
'rde1edge' as per the updated product names.

Change-Id: I14e9b0332851798531de21d70eb54f1e5557a7bd
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
diff --git a/readme.rst b/readme.rst
index 2d7af75..ae9ca80 100644
--- a/readme.rst
+++ b/readme.rst
@@ -194,7 +194,7 @@
 
 -  Allwinner sun50i_64 and sun50i_h6
 -  Amlogic Meson S905 (GXBB)
--  Arm SGI-575, RDN1Edge, SGI Clark.H and SGM-775
+-  Arm SGI-575, RDN1Edge, RDE1Edge and SGM-775
 -  Arm Neoverse N1 System Development Platform
 -  HiKey, HiKey960 and Poplar boards
 -  Marvell Armada 3700 and 8K