arm, logbuffer: make it compileclean

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/common/cmd_log.c b/common/cmd_log.c
index 0e89357..249614f 100644
--- a/common/cmd_log.c
+++ b/common/cmd_log.c
@@ -68,7 +68,7 @@
 
 unsigned long __logbuffer_base(void)
 {
-	return CONFIG_SYS_SDRAM_BASE + gd->bd->bi_memsize - LOGBUFF_LEN;
+	return CONFIG_SYS_SDRAM_BASE + gd->ram_size - LOGBUFF_LEN;
 }
 unsigned long logbuffer_base (void) __attribute__((weak, alias("__logbuffer_base")));