pkg/osutil: fix arm build
pkg/osutil: fix arm build

pkg/osutil/osutil_linux.go:44:13: cannot use info.Totalram (type uint32) as type uint64 in return argument

xairy/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller