Merge patch series "Handoff bloblist from previous boot stage"

Raymond Mao <raymond.mao@linaro.org> says:

This patch set adds/adapts a few bloblist APIs and implements Arm arch
custom function to retrieve the bloblist (aka. Transfer List) from
previous loader via boot arguments when BLOBLIST option is enabled and
all boot arguments are compliant to the register conventions defined
in the Firmware Handoff spec v0.9.

If an arch wishes to have different behaviors for loading bloblist
from the previous boot stage, it is required to implement the custom
function xferlist_from_boot_arg().