powerpc: Fix up some compile errors in the PCI error recovery code

<asm/systemcfg.h> is gone now, and the PCI error recovery constants
in include/linux/pci.h changed their names in the process of getting
accepted.

Signed-off-by: Paul Mackerras <paulus@samba.org>
(cherry picked from 5a2516156c591fc3d2059fbd93f97e15eb6010d6 commit)