Update release notes:

Update release notes:
	FREEBSD32 syscall translation layer now supports
	addition/removal of syscall from kernel module,
	VFS_AIO syscalls added to FREEBSD32,
	ktr(4) new tracepoint for callout added,
	cpufreq(4) hw.est.msr_info added,
	kern.timecounter.invariant_tsc for i386 and amd64 added,
	vfs.lookup_shared improvement and removal of LOOKUP_SHARED option, and
	netstat(1) -ss for icmp6 section fixed.

Approved by:	re (implicit)

git-svn-id: svn://svn.freebsd.org/base/releng/7.2@191521 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f