ARM: dts: imx: ba16: add "mfg" Q7 SPI-NOR partition

Add the 4th partiton named "mfg" with a block size 64K to store
manufacturing data.

Signed-off-by: Ken Lin <ken.lin@advantech.com.tw>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>