buildroot

configs/solidrun_macchiatobin_*: use a Git commit for ATF

The version of the ARM Trusted Firmware from Marvell was a Git branch,
not a Git commit, leading to unreproducible results. So let's use a
Git commit instead, which is the latest available from the branch that
was previously used.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Tested-by:  Sergey Matyukevich <geomatsi@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>