drm/i915/gvt: stop using drm_edid_block_valid()

We'll want to stop drm_edid_block_valid() usage. KVMGT is the last
user. Replace with drm_edid_valid(), which unfortunately requires an
allocated drm_edid. However, on the plus side, this would be required to
handle the TODO comment about EDID extension block support.

Acked-by: Zhi Wang <zhiwang@kernel.rog>
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240812142849.1588006-1-jani.nikula@intel.com


Signed-off-by: Jani Nikula <jani.nikula@intel.com>