Set default spec dirs at config level

This change sets the default CDI spec dirs at a config level instead
of when a CDI runtime modifier is constructed. This makes this setting
consistent with other options such as the nvidia-ctk path.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/config/config.go

@@ -151,6 +151,7 @@ func getDefault() (*Config, error) {
 				CDI: cdiModeConfig{
 					DefaultKind:        "nvidia.com/gpu",
 					AnnotationPrefixes: []string{cdi.AnnotationPrefix},
+					SpecDirs:           cdi.DefaultSpecDirs,
 				},
 			},
 		},