[PARISC] Allow nested interrupts

Our prior mode of operation didn't allow nested interrupts
because it makes the interrupt code much simpler.  However,
nested interrupts are better for latency.

This code uses the EIEM register to simulate level interrupts
and thus achieve nesting.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
diff --git a/include/asm-parisc/irq.h b/include/asm-parisc/irq.h
index 6e29cfa..399c819 100644
--- a/include/asm-parisc/irq.h
+++ b/include/asm-parisc/irq.h
@@ -39,6 +39,8 @@
  */
 void no_ack_irq(unsigned int irq);
 void no_end_irq(unsigned int irq);
+void cpu_ack_irq(unsigned int irq);
+void cpu_end_irq(unsigned int irq);
 
 extern int txn_alloc_irq(unsigned int nbits);
 extern int txn_claim_irq(int);