sandbox: Add a -N flag to control on-host behaviour

Sandbox is its own architecture, but sometimes we want to mimic the host
architecture, e.g. when running an EFI app not built by U-Boot.

Add a -N/--native flag which tells sandbox to reflect the architecture
of the host.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/include/asm/state.h b/arch/sandbox/include/asm/state.h
index e7dc017..dc21a62 100644
--- a/arch/sandbox/include/asm/state.h
+++ b/arch/sandbox/include/asm/state.h
@@ -101,6 +101,7 @@
 	bool disable_eth;		/* Disable Ethernet devices */
 	bool disable_sf_bootdevs;	/* Don't bind SPI flash bootdevs */
 	bool upl;			/* Enable Universal Payload (UPL) */
+	bool native;			/* Adjust to reflect host arch */
 
 	/* Pointer to information for each SPI bus/cs */
 	struct sandbox_spi_info spi[CONFIG_SANDBOX_SPI_MAX_BUS]