common/sfc_efx/base: add efsys API to find a memory BAR
common/sfc_efx/base: add efsys API to find a memory BAR

Function control window lookup needs memory BARs handles to
search Xilinx capabilities tables.

Define an API to get a memory BAR handle by a PCIe device handle and
BAR index.

Signed-off-by: Igor Romanov <945ea196dab32ad63762a1b623439a95515e898a@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <ac94ab2a8fe9a9a087f6e24dcbc16626b52c07e8@solarflare.com>
Reviewed-by: Andy Moreton <adbee5d9b6a6a553b71b14302d03837591e26c9d@xilinx.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk