HID: intel-ish-hid: ipc: make ish suspend paths clear

For suspend-to-idle, send suspend message and set N0_D3 flag to put
the ISH into D0i3 state.
For suspend-to-mem, disable the DMA bit before ISH entering D3, and
NO_D3 flag is cleared by default, then the ISH would enter D3.

Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>