habanalabs: add comment for pll frequency ioctl opcode

Forgot to add the comment for the opcode when it was added.

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