perf perf_regs: Accurately compute register names for CSKY

perf perf_regs: Accurately compute register names for CSKY

CSKY needs the e_flags to determine the ABI level and know whether
additional registers are encoded or not. Wire this up now that the
e_flags for a thread can be determined.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Aditya Bodkhe <aditya.b1@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergei Trofimovich <slyich@gmail.com>
Cc: Shimin Guo <shimin.guo@skydio.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Swapnil Sapkal <swapnil.sapkal@amd.com>
Cc: Tianyou Li <tianyou.li@intel.com>
[ Conditionally define EF_CSKY_ABIMASK and EF_CSKY_ABIV2 for older distros ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>