perf intel-pt: Fix PEBS sample for XMM registers

perf intel-pt: Fix PEBS sample for XMM registers

The condition to add XMM registers was missing, the regs array needed to
be in the outer scope, and the size of the regs array was too small.

Fixes: 09f8fd4e1bea2 ("perf intel-pt: Add XMM registers to synthesized PEBS sample")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Luwei Kang <luwei.kang@intel.com>
Link: http://lore.kernel.org/lkml/20200630133935.11150-4-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>