Move board_init_f_mem() into a common location

This function will be used by both SPL and U-Boot proper. So move it into
a common place. Also change the #ifdef so that the early malloc() area is
not set up in SPL if CONFIG_SYS_SPL_MALLOC_START is defined. In that case
it would never actually be used, and just chews up stack space.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/init/board_init.c b/common/init/board_init.c
new file mode 100644
index 0000000..e7ebca7
--- /dev/null
+++ b/common/init/board_init.c
@@ -0,0 +1,41 @@
+/*
+ * Code shared between SPL and U-Boot proper
+ *
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Unfortunately x86 can't compile this code as gd cannot be assigned */
+#ifndef CONFIG_X86
+__weak void arch_setup_gd(struct global_data *gd_ptr)
+{
+	gd = gd_ptr;
+}
+#endif /* !CONFIG_X86 */
+
+ulong board_init_f_mem(ulong top)
+{
+	struct global_data *gd_ptr;
+
+	/* Leave space for the stack we are running with now */
+	top -= 0x40;
+
+	top -= sizeof(struct global_data);
+	top = ALIGN(top, 16);
+	gd_ptr = (struct global_data *)top;
+	memset(gd_ptr, '\0', sizeof(*gd));
+	arch_setup_gd(gd_ptr);
+
+#if defined(CONFIG_SYS_MALLOC_F)
+	top -= CONFIG_SYS_MALLOC_F_LEN;
+	gd->malloc_base = top;
+#endif
+
+	return top;
+}