drm/hisilicon/hibmc: Add vga connector detect functions

Because the connected VGA connector would make driver can't get the
userspace call, adding detect_ctx in vga connector to make HPD active
userspace.

Signed-off-by: Baihan Li <libaihan@huawei.com>
Signed-off-by: Yongbang Shi <shiyongbang@huawei.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20250331074212.3370287-10-shiyongbang@huawei.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>