drm/xe: Drop VM dma-resv lock on xe_sync_in_fence_get failure in exec IOCTL

Upon failure all locks need to be dropped before returning to the user.

Fixes: 58480c1c ("drm/xe: Skip VMAs pin when requesting signal to the last XE_EXEC")
Cc: <stable@vger.kernel.org>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241105043524.4062774-3-matthew.brost@intel.com