PCI/AER: Use for_each_set_bit() to simplify code

Simplify error counting code by using for_each_set_bit() library function.

Link: https://lore.kernel.org/r/20190827151823.75312-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>