refactor(sgi): move from "sgi" to "neoverse_rd"

Currently, reference design platforms such as RD-N2, RD-N1-Edge,
RD-V1-MC, RD-V1 and SGI-575 utilize "css/sgi" as the common source
directory. The "sgi" prefix originated from the System Guidance for
Infrastructure (SGI) and was initially associated with the SGI-575
platform. However, subsequent platforms released were under the Neoverse
Reference Design product name.

To align with the Neoverse Reference Design nomenclature, rename the
common source directory from "css/sgi" to "css/neoverse_rd" and update
all file prefixes from "sgi" to "nrd."

Signed-off-by: Rohit Mathew <Rohit.Mathew@arm.com>
Change-Id: I3dcbb31b9ab202e82caf25218ba33c520dcea4e4
diff --git a/plat/arm/css/neoverse_rd/nrd_topology.c b/plat/arm/css/neoverse_rd/nrd_topology.c
new file mode 100644
index 0000000..40be049
--- /dev/null
+++ b/plat/arm/css/neoverse_rd/nrd_topology.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2018-2024, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <plat/arm/common/plat_arm.h>
+
+/*
+ * Common topology related methods for SGI and RD based platforms
+ */
+/*******************************************************************************
+ * This function returns the core count within the cluster corresponding to
+ * `mpidr`.
+ ******************************************************************************/
+unsigned int plat_arm_get_cluster_core_count(u_register_t mpidr)
+{
+	return CSS_SGI_MAX_CPUS_PER_CLUSTER;
+}
+
+#if ARM_PLAT_MT
+/******************************************************************************
+ * Return the number of PE's supported by the CPU.
+ *****************************************************************************/
+unsigned int plat_arm_get_cpu_pe_count(u_register_t mpidr)
+{
+	return CSS_SGI_MAX_PE_PER_CPU;
+}
+#endif