ANDROID: Fix CRC issue up with xfrm headers in 5.4.174

Two changes to net/xfrm/xfrm_policy.c in the 5.4.174 release ended up
changing the CRC for a xfrm function, despite no actual change
happening.  Fix this up by putting __GENKSYMS__ bounds on the include
files to preserve the CRC.

Bug: 161946584
Fixes: 1e06cb37 ("xfrm: Don't accidentally set RTO_ONLINK in decode_session4()")
Fixes: e8951408 ("xfrm: fix policy lookup for ipv6 gre packets")
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ia09ea8d4439ec276716396f40dc82c0958624690