sandbox: Add a dummy booti command

Add basic sandbox support for 'booti' so we can start to boot the test
ARMbian image. This is helpful in checking that it is parsed correctly.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/lib/bootm.c b/arch/sandbox/lib/bootm.c
index dc8b8e4..a748ba6 100644
--- a/arch/sandbox/lib/bootm.c
+++ b/arch/sandbox/lib/bootm.c
@@ -78,3 +78,10 @@
 
 	return 0;
 }
+
+/* used for testing 'booti' command */
+int booti_setup(ulong image, ulong *relocated_addr, ulong *size,
+		bool force_reloc)
+{
+	return 0;
+}
diff --git a/cmd/Kconfig b/cmd/Kconfig
index bebe816..748b959 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -285,7 +285,7 @@
 
 config CMD_BOOTI
 	bool "booti"
-	depends on ARM64 || RISCV
+	depends on ARM64 || RISCV || SANDBOX
 	default y
 	help
 	  Boot an AArch64 Linux Kernel image from memory.
diff --git a/cmd/booti.c b/cmd/booti.c
index 2db8f4a..41d40c9 100644
--- a/cmd/booti.c
+++ b/cmd/booti.c
@@ -75,7 +75,7 @@
 	unmap_sysmem((void *)ld);
 
 	ret = booti_setup(ld, &relocated_addr, &image_size, false);
-	if (ret != 0)
+	if (ret || IS_ENABLED(CONFIG_SANDBOX))
 		return 1;
 
 	/* Handle BOOTM_STATE_LOADOS */
diff --git a/configs/tools-only_defconfig b/configs/tools-only_defconfig
index fa1ff4a..b54d2ce 100644
--- a/configs/tools-only_defconfig
+++ b/configs/tools-only_defconfig
@@ -16,6 +16,7 @@
 CONFIG_BOOTCOMMAND="run distro_bootcmd"
 # CONFIG_CMD_BOOTD is not set
 # CONFIG_CMD_BOOTM is not set
+# CONFIG_CMD_BOOTI is not set
 # CONFIG_CMD_ELF is not set
 # CONFIG_CMD_EXTENSION is not set
 # CONFIG_CMD_DATE is not set