drm/amd/display: remove unused struct 'aux_payloads'

'aux_payloads' is unused since
commit eae5ffa9bd7b ("drm/amd/display: Switch ddc to new aux interface")
Remove it.

Signed-off-by: Dr. David Alan Gilbert <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/link/protocols/link_ddc.c

···
 	struct vector payloads;
 };
 
-struct aux_payloads {
-	struct vector payloads;
-};
-
 static bool i2c_payloads_create(
 		struct dc_context *ctx,
 		struct i2c_payloads *payloads,