bus/pci: optimise scanning with whitelist/blacklist

bus/pci: optimise scanning with whitelist/blacklist

rte_bus_scan API scans all the available PCI devices irrespective of white
or black listing parameters then further devices are probed based on white
or black listing parameters. So unnecessary CPU cycles are wasted during
rte_pci_scan.

For Octeontx2 platform with core frequency 2.4 Ghz, rte_bus_scan consumes
around 26ms to scan around 90 PCI devices but all may not be used by the
application. So for the application which uses 2 NICs, rte_bus_scan
consumes few microseconds and rest time is saved with this patch.

Patch restricts devices to be scanned as per below mentioned conditions:
 - All devices will be scanned if no parameters are passed.
 - Only white listed devices will be scanned if white list is available.
 - All devices, except black listed, will be scanned if black list is
   available.

Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
Acked-by: Gaetan Rivet <grive@u256.net>