Create a new boot/ directory

Quite a lot of the code in common/relates to booting and images. Before
adding more it seems like a good time to move the code into its own
directory.

Most files with 'boot' or 'image' in them are moved, except:

- autoboot.c which relates to U-Boot automatically running a script
- bootstage.c which relates to U-Boot timing

Drop the removal of boot* files from the output directory, since this
interfers with the symlinks created by tools and there does not appear
to be any such file from my brief testing.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Artem Lapkin <email2tema@gmail.com>
Tested-by: Artem Lapkin <email2tema@gmail.com>

boot/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));
+}