turnip: Fix file descriptor return.
Fix defect reported by Coverity Scan.
Logically dead code (DEADCODE) dead_error_line: Execution cannot reach the expression -1 inside this statement: return ret ? -1 : handle.fd;
Fixes: 8163c818 ("turnip: implement timestamp fences/semaphores for kgsl backend") Signed-off-by: Vinson Lee vlee@freedesktop.org