Instead of waiting for BTM indication we should wait for preboot ready.
Consider the below scenario:
    1. FW update is being triggered
           - setting the dirty bit
    2. hard reset will be triggered due to the dirty bit
    3. FW initiates the reset:
           - dirty bit cleared
           - BTM indication cleared
           - preboot ready indication cleared
    4. during hard reset:
           - BTM indication will be set
           - BIST test performed and another reset triggered
    5. only after this reset the preboot will set the preboot ready

When polling on BTM indication alone we can lose sync with FW while
trying to communicate with FW that is during reset.
To overcome this we will always wait to preboot ready indication.
Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>