drm/amd/display/dc/core/dc_link_dp: Move DP_VGA_LVDS_CONVERTER_ID_{2, 3} to where they're used

This patch fixes >200 warnings.

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/amd/amdgpu/../display/include/ddc_service_types.h:123:22: warning: ‘DP_VGA_LVDS_CONVERTER_ID_3’ defined but not used [-Wunused-const-variable=]
 123 | static const uint8_t DP_VGA_LVDS_CONVERTER_ID_3[] = "dnomlA";
 | ^~~~~~~~~~~~~~~~~~~~~~~~~~
 drivers/gpu/drm/amd/amdgpu/../display/include/ddc_service_types.h:121:22: warning: ‘DP_VGA_LVDS_CONVERTER_ID_2’ defined but not used [-Wunused-const-variable=]
 121 | static const uint8_t DP_VGA_LVDS_CONVERTER_ID_2[] = "sivarT";

NB: Repeated ~100 times - snipped for brevity

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>