habanalabs: use variable poll interval for fw loading

Using a variable poll interval for fw loading allows us to support
much slower environments (emulation) while changing only a single
line in the code, instead of choosing a different interval in each
function that polls.

Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>