feat(plat/arm): add memory map entry for CPER memory region

In firmware-first error handling approach the firmware consumes the
hardware fault interrupt, processes the error and notifies the fault to
OSPM. Firmware also shares the error information with the OSPM using a
standard format called Common Platform Error Record (CPER). The CPER is
placed in reserved memory that is shared between OSPM and the firmware.
On RD-N2 platform variants carve out a reserved memory space for the
CPER buffer. This patch enables CPER memory map region on RD-N2 platform
variants.

Signed-off-by: Omkar Anand Kulkarni <omkar.kulkarni@arm.com>
Change-Id: Ib2645c90d4dc975f57bb143795f61f74f4f81494
diff --git a/plat/arm/css/sgi/sgi_plat_v2.c b/plat/arm/css/sgi/sgi_plat_v2.c
index 8d38108..8de0efe 100644
--- a/plat/arm/css/sgi/sgi_plat_v2.c
+++ b/plat/arm/css/sgi/sgi_plat_v2.c
@@ -87,6 +87,9 @@
 	SOC_PLATFORM_PERIPH_MAP_DEVICE_USER,
 	ARM_SP_IMAGE_MMAP,
 	ARM_SP_IMAGE_NS_BUF_MMAP,
+#if RAS_FFH_SUPPORT
+	CSS_SGI_SP_CPER_BUF_MMAP,
+#endif
 	ARM_SP_IMAGE_RW_MMAP,
 	ARM_SPM_BUF_EL0_MMAP,
 	{0}