dxvk: use $W_TMP_EARLY rather than $W_TMP

$W_TMP breaks under winetricks-test, since it is inside the prefix,
which contains '-', which w_download_to() balks at.

src/winetricks

@@ -6798,8 +6798,8 @@ load_dxvk()
 {
     # https://github.com/doitsujin/dxvk
     # There's no stable exe URL, but they do provide a RELEASE file that lets us build one:
-    w_download_to "$W_TMP" "https://raw.githubusercontent.com/doitsujin/dxvk/master/RELEASE"
-    dxvk_version="$(cat "${W_TMP}/RELEASE")"
+    w_download_to "${W_TMP_EARLY}" "https://raw.githubusercontent.com/doitsujin/dxvk/master/RELEASE"
+    dxvk_version="$(cat "${W_TMP_EARLY}/RELEASE")"
     w_linkcheck=1_ignore w_download "https://github.com/doitsujin/dxvk/releases/download/v${dxvk_version}/dxvk-${dxvk_version}.tar.gz"
     helper_dxvk "dxvk-${dxvk_version}.tar.gz" "3.10" "1.0.76"
     unset dxvk_version