zink: initialize drm_fd to -1

zink: initialize drm_fd to -1

The `zink_internal_create_screen()` function initializes
`screen->drm_fd` to 0, a valid file descriptor value, via `rzalloc`.

If an error is found during initialization, the `zink_destroy_screen()`
function is invoked in the `fail` label and the `screen->drm_fd` is
closed because its value is 0 and `screen->drm_fd != -1` is checked.

Initialize `screen->drm_fd` to -1 to avoid this issue.

Resolves: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10191
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Signed-off-by: José Expósito <jexposit@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26332>
(cherry picked from commit fff3fc45a0125b408ca8d4dbd48e5633d63ccc5a)