scripts/namespace.pl: improve to get more correct results
Exclude more symbols from arch/x86/vdso/ and arch/x86/boot/; add some more
linker-defined symbols into exception list; add other cond_syscalls
besides "sys_*".
Signed-off-by: Amerigo Wang <amwang@redhat.com> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Marek <mmarek@suse.cz>