bpf: adjust bpf_ts on FreeBSD

[evverx]

to get scapy to capture packets on both 32-bit and 64-bit machines.

The bpf_ts structure contains two 64-bit fields:
https://github.com/freebsd/freebsd-src/blob/aea4240ef5834fb4a47f80c659c80f902cb4bb06/sys/net/bpf.h#L206-L209

struct bpf_ts {
	bpf_int64	bt_sec;		/* seconds */
	bpf_u_int64	bt_frac;	/* fraction */
};

and it has been this way since it was introduced in freebsd/freebsd-src@547d94b back in 2010.

Introduce new time stamp 'struct bpf_ts' and header 'struct bpf_xhdr'.
The new time stamp has both 64-bit second and fractional parts.  bpf_xhdr
has this time stamp instead of 'struct timeval' for bh_tstamp.  The new
structures let us use bh_tstamp of same size on both 32-bit and 64-bit
platforms without adding additional shims for 32-bit binaries.

It was tested on FreeBSD 14.4-RELEASE/i386 and 15.1-RELEASE-p2/amd64.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 80.31%. Comparing base (d8f7b27) to head (c68f0ab).

Files with missing lines	Patch %	Lines
scapy/arch/bpf/supersocket.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5077      +/-   ##
==========================================
- Coverage   80.48%   80.31%   -0.18%     
==========================================
  Files         390      390              
  Lines       96810    96810              
==========================================
- Hits        77917    77750     -167     
- Misses      18893    19060     +167     

Files with missing lines	Coverage Δ
scapy/arch/bpf/supersocket.py	71.84% <0.00%> (ø)

... and 19 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.