
In this PR, we remove `.pin_memory()` in `obj_pos` of `SAM2Base` to resolve and error in MPS. Investigations show that `.pin_memory()` causes an error of `Attempted to set the storage of a tensor on device "cpu" to a storage on different device "mps:0"`, as originally reported in https://github.com/facebookresearch/sam2/issues/487. (close https://github.com/facebookresearch/sam2/issues/487)