Sync linux headers to 4.19.66

Sync linux headers to 4.19.66

This fixes the build with musl libc.

Additionally, several changes were made to account for changes to the
headers:

- ip_mp_alg.h was removed, since it was removed in linux commit e06e7c61
  (v2.6.23), and the last use of those constants was removed in libnl
  commit 535e8316.
- Uses of TCF_META_ID_SK_ROUTE_CAPS were updated to
  __TCF_META_ID_SK_ROUTE_CAPS, since it was renamed in linux commit
  e20e6940 (v3.1).
- Uses of IF_CARRIER_DOWN and IF_CARRIER_UP were replaced with their
  values, 0 and 1, since they are not in linux/if.h (they appear to be
  libnl-specific, added in libnl commit 3540e44b).

https://github.com/thom311/libnl/pull/222