qcom: pil-msa: Move freeing DMA memory till after MBA authenticates image

Although the MBA image is copied and executed from L2 memory,
the 1MB of DDR memory that was initially allocated for the
image is still used by MBA.
Thus move freeing this memory from the init_image operation
till until the auth_and_reset operation is successful.

Change-Id: I578bc6fc89c501d02ab25c50f32f52c5b6e386ce
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>