s390: use SPARSE_IRQ

Use dynamically allocated irq descriptors on s390 which allows
us to get rid of the s390 specific config option PCI_NR_MSI and
exploit more MSI interrupts. Also the size of the kernel image
is reduced by 131K (using performance_defconfig).

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h
index f97b055..70c9bce 100644
--- a/arch/s390/include/asm/irq.h
+++ b/arch/s390/include/asm/irq.h
@@ -7,11 +7,8 @@
 
 #define NR_IRQS_BASE	3
 
-#ifdef CONFIG_PCI_NR_MSI
-# define NR_IRQS	(NR_IRQS_BASE + CONFIG_PCI_NR_MSI)
-#else
-# define NR_IRQS	NR_IRQS_BASE
-#endif
+#define NR_IRQS	NR_IRQS_BASE
+#define NR_IRQS_LEGACY NR_IRQS_BASE
 
 /* External interruption codes */
 #define EXT_IRQ_INTERRUPT_KEY	0x0040