amdgpu/dm: Default PRE_VEGA ASIC support to 'y'

Even though we default PRE_VEGA support to 'n' upstream in amd-staging
we want to keep it enabled by default.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/Kconfig

@@ -11,7 +11,7 @@ config DRM_AMD_DC
 
 config DRM_AMD_DC_PRE_VEGA
 	bool "DC support for Polaris and older ASICs"
-	default n
+	default y
 	help
 	  Choose this option to enable the new DC support for older asics
 	  by default. This includes Polaris, Carrizo, Tonga, Bonaire,