uboot-phytec

test/py: avb: fix test_avb_persistent_values fail

Fix test_avb_persistent_values() pytest, which was failing because of
wrong size value provided from tee sandbox driver.

Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Igor Opaniuk <igor.opaniuk@gmail.com>