HID: intel-ish-hid: initialize ts_format.reserved

ts_format.reserved is not used anywhere yet, but the compiler generates a
warning when the struct's (uninitialized) field is being copied around

drivers/hid/intel-ish-hid/ipc/ipc.c: In function ‘write_ipc_from_queue’:
drivers/hid/intel-ish-hid/ipc/ipc.c:316: warning: ‘ts_format.reserved’ may be used uninitialized in this function

Avoid this by force-initializing the field to zero.

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