perf annotate: Propagate perf_env__arch() error

The callers of symbol__annotate2() use symbol__strerror_disassemble() to
convert its failure returns into a human readable string, so
propagate error values from functions it calls, starting with
perf_env__arch() that when fails the right thing to do is to look at
'errno' to see why its possible call to uname() failed.

Reported-by: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Cc: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/n/tip-it5d83kyusfhb1q1b0l4pxzs@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>