perf evsel: Add bitfield_swap() to handle branch_stack endian issue

perf evsel: Add bitfield_swap() to handle branch_stack endian issue

The branch_stack struct has bit field definition which produces
different bit ordering for big/little endian.

Because of this, when branch_stack sample is collected in a BE system
and viewed/reported in a LE system, bit fields of the branch stack are
not presented properly.

To address this issue, a evsel__bitfield_swap_branch_stack() is defined
and introduced in evsel__parse_sample.

Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20211028113714.600549-1-maddy@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>