Kernel 6.1.y backports for "dma-buf: keep the signaling time of merged fences v3"

Hi,

Please help backport following two commits to 6.1.y

f781f661e8c9 dma-buf: keep the signaling time of merged fences v3 00ae1491f970 dma-buf: fix an error pointer vs NULL bug

The first one is to fix some Android CTS failures founded with android14-6.1 GKI kernel. run cts -m CtsDeqpTestCases -t dEQP-EGL.functional.get_frame_timestamps* The second patch is to fix the error introduced by the first one.

Thanks!