sparc64: Fix OOPS in psycho_pcierr_intr_other().

We no longer put the top-level PCI controller device into the
PCI layer device list.  So pbm->pci_bus->self is always NULL.

Therefore, use direct PCI config space accesses to get at
the PCI controller's PCI_STATUS register.

Tested by Meelis Roos.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/pci_psycho.c b/arch/sparc64/kernel/pci_psycho.c
index e205ade..f85b6be 100644
--- a/arch/sparc64/kernel/pci_psycho.c
+++ b/arch/sparc64/kernel/pci_psycho.c
@@ -575,7 +575,7 @@
 {
 	unsigned long csr_reg, csr, csr_error_bits;
 	irqreturn_t ret = IRQ_NONE;
-	u16 stat;
+	u16 stat, *addr;
 
 	if (is_pbm_a) {
 		csr_reg = pbm->controller_regs + PSYCHO_PCIA_CTRL;
@@ -597,7 +597,9 @@
 			printk("%s: PCI SERR signal asserted.\n", pbm->name);
 		ret = IRQ_HANDLED;
 	}
-	pci_read_config_word(pbm->pci_bus->self, PCI_STATUS, &stat);
+	addr = psycho_pci_config_mkaddr(pbm, pbm->pci_first_busno,
+					0, PCI_STATUS);
+	pci_config_read16(addr, &stat);
 	if (stat & (PCI_STATUS_PARITY |
 		    PCI_STATUS_SIG_TARGET_ABORT |
 		    PCI_STATUS_REC_TARGET_ABORT |
@@ -605,7 +607,7 @@
 		    PCI_STATUS_SIG_SYSTEM_ERROR)) {
 		printk("%s: PCI bus error, PCI_STATUS[%04x]\n",
 		       pbm->name, stat);
-		pci_write_config_word(pbm->pci_bus->self, PCI_STATUS, 0xffff);
+		pci_config_write16(addr, 0xffff);
 		ret = IRQ_HANDLED;
 	}
 	return ret;