board/freescale: specify the volume-label for FAT partition
Currently the volume-label for the vfat partition is a string with
the following pattern: 5934-861D.
Specify the volume-label as "boot" to make it easier to identify it.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Tested-by: Pierre-Jean Texier <pjtexier@koncepto.io>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>