Revert "DPE: Reuse command buffer to decrease stack usage"

This reverts commit d0983e963e89ad8198bc221cda48164b854a844a.

Reason for revert: Size of output buf provided by client may be less than
DICE_CERT_SIZE/DICE_CERT_CHAIN_SIZE and hence can underflow.

Signed-off-by: Maulik Patel <maulik.patel@arm.com>
Change-Id: I78b05876eee595676927eff71698ae34b3e3c3cc
1 file changed