configs/stm32mp157a_dk1: bump TF-A, Linux, U-Boot versions

configs/stm32mp157a_dk1: bump TF-A, Linux, U-Boot versions

Runtime tested:

NOTICE:  Model: STMicroelectronics STM32MP157A-DK1 Discovery Board
NOTICE:  Board: MB1272 Var1.0 Rev.C-01
...
U-Boot 2021.07 (Jul 09 2021 - 20:53:05 +0200)
...
Starting kernel ...

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 5.13.0 ...
...
Welcome to Buildroot
buildroot login:

Signed-off-by: Pierre-Jean Texier <texier.pj2@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>