Add missing headers to 'make dist' target for RPM build

The following files were being left out the tarball which
is used by the 'make rpm' target.  This results in a build
failure when building packages which use the tarball.

        lib/libspl/include/sys/tsol/*.h
        lib/libspl/include/util/*.h

lib/libspl/include/Makefile.am

@@ -4,4 +4,6 @@ nobase_pkginclude_HEADERS += rpc/*.h
 nobase_pkginclude_HEADERS += sys/*.h
 nobase_pkginclude_HEADERS += sys/dktp/*.h
 nobase_pkginclude_HEADERS += sys/sysevent/*.h
+nobase_pkginclude_HEADERS += sys/tsol/*.h
 nobase_pkginclude_HEADERS += tsol/*.h
+nobase_pkginclude_HEADERS += util/*.h