edac: ibecc: Simplify PCI probing
edac: ibecc: Simplify PCI probing

Use only one pcie_conf_read() instead of several reads and make code
more readable.

Signed-off-by: Andrei Emeltchenko <a6565233ddc88e4fb9c66c1d70743223493f2ed4@intel.com>

galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr