drm/mediatek: mtk_hdmi: Fix typo for aud_sampe_size member

drm/mediatek: mtk_hdmi: Fix typo for aud_sampe_size member

Rename member aud_sampe_size of struct hdmi_audio_param to
aud_sample_size to fix a typo and enhance readability.

This commit brings no functional changes.

Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20250217154836.108895-20-angelogioacchino.delregno@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>