Remove unused Autoconf checks for socket structs

[petk]

• struct cmsghdr is not used in the Swoole code
• the sockaddr_storage.ss_family used to be checked for AIX versions 5.3 and older, which contained __ss_family instead. On AIX 6 and later the ss_family field is available.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (9c08e1a) 72.97% compared to head (e8fe7e6) 72.93%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5253      +/-   ##
==========================================
- Coverage   72.97%   72.93%   -0.05%     
==========================================
  Files          69       69              
  Lines       14858    14858              
==========================================
- Hits        10843    10836       -7     
- Misses       4015     4022       +7     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.