media: iris: Fix buffer count reporting in internal buffer check

Initialize the count variable to zero before counting unreleased
internal buffers in iris_check_num_queued_internal_buffers().
This prevents stale values from previous iterations and ensures accurate
error reporting for each buffer type. Without this initialization, the
count could accumulate across types, leading to incorrect log messages.

Fixes: d2abb1ff ("media: iris: Verify internal buffer release on close")
Cc: stable@vger.kernel.org
Reviewed-by: Vikash Garodia <quic_vgarodia@quicinc.com>
Tested-by: Vikash Garodia <quic_vgarodia@quicinc.com> # X1E80100
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-HDK
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-HDK
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> # x1e80100-crd
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>