blinky: Remove Starting bootloader line from pass output

Starting bootloader printed by BL2.
Corstone-300 and 310 starting the BL2 first,
than do the provisioning part.
Corstone-315 do the provisioning first, because of the
BL1 ROM bootloader, therefore the log messages
comes swapped from this platform.
We have deleted the Starting bootloader line to
unify the pass output file.

Signed-off-by: Dávid Házi <david.hazi@arm.com>