perf annotate: Fix the signedness of failure returns

Callers of symbol__annotate() expect a errno value or some other
extended error value range in symbol__strerror_disassemble() to
convert to a proper error string, fix it when propagating a failure to
find the arch specific annotation routines via arch__find(arch_name).

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-o0k6dw7cas0vvmjjvgsyvu1i@git.kernel.org


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