cmd: mvebu/bubt: Add support for writing image to SATA disk

All 32-bit Armada SoCs and also 64-bit Armada 3720 SoC can load and boot
firmware from SATA disk. This adds support for updating firmware binary for
these SoCs. On 32-bit Armada SoC is firmware stored at sector 1 and on
Armada 3720 is stored at MBR partition 0x4d or GPT partition with type GUID
6828311A-BA55-42A4-BCDE-A89BB5EDECAE (Marvell Armada 3700 Boot partition).

Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/doc/mvebu/cmd/bubt.txt b/doc/mvebu/cmd/bubt.txt
index 1fe1f07..515e4fb 100644
--- a/doc/mvebu/cmd/bubt.txt
+++ b/doc/mvebu/cmd/bubt.txt
@@ -5,7 +5,7 @@
 The bubt command gets the following parameters: ATF file name, destination device and source device.
 bubt [file-name] [destination [source]]
 	- file-name		Image file name to burn. default = flash-image.bin
-	- destination		Flash to burn to [spi, nand, mmc]. default = active flash
+	- destination		Flash to burn to [spi, nand, mmc, sata]. default = active flash
 	- source		Source to load image from [tftp, usb]. default = tftp
 
 Examples: