ext4: fix memory leak in ext4_ext_shift_extents()

In the Linux kernel, the following vulnerability has been resolved: ext4: fix memory leak in ext4_ext_shift_extents() In ext4_ext_shift_extents(), if the extent is NULL in the while loop, the function returns immediately without releasing the path obtained via ext4_find_extent(), leading to a memory leak. Fix this by jumping to the out label to ensure the path is properly released.