thunderbolt: switch: Fix function name in the header

commit 2c2a2327 upstream.

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

 drivers/thunderbolt/switch.c:1322: warning: expecting prototype for reset_switch(). Prototype was for tb_switch_reset() instead

Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: Yehezkel Bernat <YehezkelShB@gmail.com>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>