simpleperf: fix x86 register dump on x86_64.

x86_64 linux kernel doesn't support dumping registers like DS.
If simpleperf32 requests dumping these registers, it will fail.
So don't request them to avoid failure.

Bug: None.
Test: run simpleperf32 manually on x86_64.
Change-Id: I220ce5378bad8f0c3c9deb2ef32128fd3262b96d
1 file changed