Input: ims-pcu - sanity check against missing interfaces

A malicious device missing interface can make the driver oops.
Add sanity checking.

Signed-off-by: Oliver Neukum <ONeukum@suse.com>
CC: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
static void ims_pcu_report_events(struct ims_pcu *pcu)
{
	u32 data = get_unaligned_be32(&pcu->read_buf[3]);

	ims_pcu_buttons_report(pcu, data & ~IMS_PCU_GAMEPAD_MASK);
	if (pcu->gamepad)
		ims_pcu_gamepad_report(pcu, data);
}

static void ims_pcu_report_events(struct ims_pcu *pcu)
{
	u32 data = get_unaligned_be32(&pcu->read_buf[3]);

	ims_pcu_buttons_report(pcu, data & ~IMS_PCU_GAMEPAD_MASK);
	if (pcu->gamepad)
		ims_pcu_gamepad_report(pcu, data);
}
