2 Function prevent this crate to be used on smaller hardware (ESP32)

[hcabel]

He, I wanted to use another crate that depend on this one (usbd-human-interface-device), on my ESP32-S3 and sadly it wouldn't compile :/

The reason is that ESP32 (and probably other microcontrollers) doesn't support AtomicU64 which is used by the bitvec crate that this one depends on. Digging into this I realize that you only use bitvec in 2 function: https://github.com/hashmismatch/packed_struct.rs/blob/0faff82db821d0dba02b8cd92e29eb8ff79d4ecd/packed_struct/src/types_num.rs#L667 and https://github.com/hashmismatch/packed_struct.rs/blob/0faff82db821d0dba02b8cd92e29eb8ff79d4ecd/packed_struct/src/types_num.rs#L687 I've personally copied everything locally and commented those out (work fine now 👍) (not qualify enough to make a PR myself)

original Issue: https://github.com/dlkj/usbd-human-interface-device/issues/164