drm/amd/display: read invalid ddc pin status cause engine busy

[Why]
There is no DDC_6 pin on new asic cause the mapping table is
incorrect. When app try to access DDC_VGA port, driver read
an invalid ddc pin status and report engine busy.

[How]
Add dummy DDC_6 pin to align gpio structure.

Reviewed-by: Alvin Lee <[e-mail]>
Acked-by: Stylon Wang <[e-mail]>
Signed-off-by: Paul Hsieh <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/gpio/dcn32/hw_factory_dcn32.c

···
  */
 void dal_hw_factory_dcn32_init(struct hw_factory *factory)
 {
-	factory->number_of_pins[GPIO_ID_DDC_DATA] = 6;
-	factory->number_of_pins[GPIO_ID_DDC_CLOCK] = 6;
+	factory->number_of_pins[GPIO_ID_DDC_DATA] = 8;
+	factory->number_of_pins[GPIO_ID_DDC_CLOCK] = 8;
 	factory->number_of_pins[GPIO_ID_GENERIC] = 4;
 	factory->number_of_pins[GPIO_ID_HPD] = 5;
 	factory->number_of_pins[GPIO_ID_GPIO_PAD] = 28;