sysinfo: Add SYSID_BOARD_RAM_SIZE_MB

Add a new field SYSID_BOARD_RAM_SIZE_MB to sysinfo structure to store
the size of RAM in MB. dram_init can use this field to get the RAM size
via sysinfo driver.

Signed-off-by: Baocheng Su <baocheng.su@siemens.com>
diff --git a/include/sysinfo.h b/include/sysinfo.h
index 2866ac2..e87cf96 100644
--- a/include/sysinfo.h
+++ b/include/sysinfo.h
@@ -153,6 +153,7 @@
 	SYSID_BOARD_MODEL,
 	SYSID_BOARD_MANUFACTURER,
 	SYSID_BOARD_MAC_ADDR,
+	SYSID_BOARD_RAM_SIZE_MB,
 	SYSID_PRIOR_STAGE_VERSION,
 	SYSID_PRIOR_STAGE_DATE,