media: atomisp: Remove isp_timeout flag

isp_timeout only ever gets set in __atomisp_css_recover() and then
immediately gets cleared again after calling atomisp_reset().

All this happens with isp->mutex held.

The only consumer of isp->isp_timeout is atomisp_stop_streaming(), which
also holds isp->mutex and which is *not* called by atomisp_reset().

Since both hold isp->mutex and since __atomisp_css_recover() clears
isp_timeout before releasing the mutex, atomisp_stop_streaming() can
never see isp_timeout being true, so just remove the flag.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>