dma-buf: fix dma_fence_default_wait() signaling check

That check must now come after grabing the spinlock, not before.

Signed-off-by: Christian König <christian.koenig@amd.com>
Fixes: b96fb1e7 ("dma-buf: dma_fence_wait must enable signaling")
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220919120618.113332-1-christian.koenig@amd.com