habanalabs: fetch pll frequency from firmware

Once firmware security is enabled, driver must fetch pll frequencies
through the firmware message interface instead of reading the registers
directly.

Signed-off-by: Alon Mizrahi <amizrahi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>