habanalabs: make print of engines idle mask more readable

The engines idle mask was increased to be an array of 4 u64 entries.
To make the print of this mask more readable, remove the "0x" prefix,
and zero-pad each u64 to 16 bytes if either it isn't zero or if any of
the higher-order u64's is not zero.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>