image: Split host code out into its own file

To avoid having #ifdefs in a few functions which are completely different
in the board and host code, create a new image-host.c file.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/image-host.c

@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Image code used by host tools (and not boards)
+ *
+ * (C) Copyright 2008 Semihalf
+ *
+ * (C) Copyright 2000-2006
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ */
+
+#include <time.h>
+
+void memmove_wd(void *to, void *from, size_t len, ulong chunksz)
+{
+	memmove(to, from, len);
+}
+
+void genimg_print_size(uint32_t size)
+{
+	printf("%d Bytes = %.2f KiB = %.2f MiB\n", size, (double)size / 1.024e3,
+	       (double)size / 1.048576e6);
+}
+
+void genimg_print_time(time_t timestamp)
+{
+	printf("%s", ctime(&timestamp));
+}