fix(sgi): reduce cper buffer carveout size

Reduce the size of the CPER buffer as it is overlapping with SP's heap
region.

Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: Iaea75a1ffb50ecf0223594fe8bffcebc16da7eab
diff --git a/plat/arm/css/sgi/include/sgi_base_platform_def.h b/plat/arm/css/sgi/include/sgi_base_platform_def.h
index 3ab07cd..dab5f8b 100644
--- a/plat/arm/css/sgi/include/sgi_base_platform_def.h
+++ b/plat/arm/css/sgi/include/sgi_base_platform_def.h
@@ -217,7 +217,7 @@
  */
 #define CSS_SGI_SP_CPER_BUF_BASE	(PLAT_SP_IMAGE_NS_BUF_BASE + \
 					 PLAT_SP_IMAGE_NS_BUF_SIZE)
-#define CSS_SGI_SP_CPER_BUF_SIZE	ULL(0x20000)
+#define CSS_SGI_SP_CPER_BUF_SIZE	ULL(0x10000)
 #define CSS_SGI_SP_CPER_BUF_MMAP	MAP_REGION2(			       \
 						CSS_SGI_SP_CPER_BUF_BASE,      \
 						CSS_SGI_SP_CPER_BUF_BASE,      \