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>
diff --git a/boot/Makefile b/boot/Makefile
new file mode 100644
index 0000000..a19e85c
--- /dev/null
+++ b/boot/Makefile
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# (C) Copyright 2004-2006
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+
+ifndef CONFIG_SPL_BUILD
+
+# This option is not just y/n - it can have a numeric value
+ifdef CONFIG_BOOT_RETRY_TIME
+obj-y += bootretry.o
+endif
+
+obj-$(CONFIG_CMD_BOOTM) += bootm.o bootm_os.o
+obj-$(CONFIG_CMD_BOOTZ) += bootm.o bootm_os.o
+obj-$(CONFIG_CMD_BOOTI) += bootm.o bootm_os.o
+
+endif
+
+obj-y += image.o image-board.o
+obj-$(CONFIG_ANDROID_AB) += android_ab.o
+obj-$(CONFIG_ANDROID_BOOT_IMAGE) += image-android.o image-android-dt.o
+obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
+obj-$(CONFIG_$(SPL_TPL_)FIT_SIGNATURE) += fdt_region.o
+obj-$(CONFIG_$(SPL_TPL_)FIT) += image-fit.o
+obj-$(CONFIG_$(SPL_)MULTI_DTB_FIT) += boot_fit.o common_fit.o
+obj-$(CONFIG_$(SPL_TPL_)IMAGE_SIGN_INFO) += image-sig.o
+obj-$(CONFIG_$(SPL_TPL_)FIT_SIGNATURE) += image-fit-sig.o
+obj-$(CONFIG_$(SPL_TPL_)FIT_CIPHER) += image-cipher.o
+
+obj-$(CONFIG_CMD_ADTIMG) += image-android-dt.o
+
+ifdef CONFIG_SPL_BUILD
+obj-$(CONFIG_SPL_LOAD_FIT) += common_fit.o
+endif