drm/amd/display: remove useless else if

Fix the following coccinelle report:
drivers/gpu/drm/amd/display/dc/dcn302/dcn302_resource.c:1357:6-8:
WARNING: possible condition with no effect (if == else)
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn302/dcn302_resource.c

@@ -1354,8 +1354,6 @@ static bool dcn302_resource_construct(
 
 	if (dc->ctx->dce_environment == DCE_ENV_PRODUCTION_DRV)
 		dc->debug = debug_defaults_drv;
-	else if (dc->ctx->dce_environment == DCE_ENV_FPGA_MAXIMUS)
-		dc->debug = debug_defaults_diags;
 	else
 		dc->debug = debug_defaults_diags;