habanalabs: expose ASIC specific PLL index

Currently the user cannot interpret the PLL information based on index
as its exposed as an integer.

This commit exposes ASIC specific PLL indexes and maps it to a generic
FW compatible index.

Signed-off-by: Bharat Jauhari <bjauhari@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>