perf annotate: Rename symbol__annotate() to symbol__disassemble()

This function will not annotate anything, it will just disassembly the
given map->dso and symbol.

It currently does this by parsing the output of 'objdump --disassemble',
but this could conceivably be done using a library or an offshot of
the kernel's instruction decoder (arch/x86/lib/inat.c), etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-2xpfl4bfnrd6x584b390qok7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>