intel_th: Remove an unused exit point from intel_th_remove()

intel_th: Remove an unused exit point from intel_th_remove()

As described in the added comment device_for_each_child() never returns
a non-zero value. So remove the corresponding error check.

This simplifies the quest to make struct bus_type::remove() return void.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20210621151246.31891-3-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>