drm/amdgpu: convert bios_hardcoded_edid to drm_edid

Instead of manually passing around 'struct edid *' and its size,
use 'struct drm_edid', which encapsulates a validated combination of
both.

As the drm_edid_ can handle NULL gracefully, the explicit checks can be
dropped.

Also save a few characters by transforming '&array[0]' to the equivalent
'array' and using 'max_t(int, ...)' instead of manual casts.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c

@@ -549,7 +549,7 @@ static int amdgpu_vkms_sw_fini(void *handle)
 
 	adev->mode_info.mode_config_initialized = false;
 
-	kfree(adev->mode_info.bios_hardcoded_edid);
+	drm_edid_free(adev->mode_info.bios_hardcoded_edid);
 	kfree(adev->amdgpu_vkms_output);
 	return 0;
 }