HID: intel-ish-hid: Fix potential copy/paste error

Fixes the following W=1 kernel build warning(s):

 In file included from drivers/hid/intel-ish-hid/ishtp-hid.c:11:
 drivers/hid/intel-ish-hid/ishtp-hid.c:263: warning: expecting prototype for ishtp_hid_probe(). Prototype was for ishtp_hid_remove() instead

Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-input@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>