Structs serialised into USB buffers in cdc_ncm are not guaranteed to produce the right bytes

[Eekle]

For example:

embassy/embassy-usb/src/class/cdc_ncm/mod.rs

Lines 94 to 101 in fd2b6c8

	#[repr(packed)]
	#[allow(unused)]
	struct NtbParameters {
	length: u16,
	formats_supported: u16,
	in_params: NtbParametersDir,
	out_params: NtbParametersDir,
	}

repr(packed) is not sufficient to guarantee that fields in memory remain in the order they are written, and endianness means that the multibyte fields might not match in memory and on the wire.