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/Kconfig b/arch/s390/Kconfig
index a8c2590..3529a28 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -163,6 +163,7 @@
 	select NO_BOOTMEM
 	select OLD_SIGACTION
 	select OLD_SIGSUSPEND3
+	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
 	select TTY
 	select VIRT_CPU_ACCOUNTING
@@ -605,16 +606,6 @@
 	  This allows you to specify the maximum number of PCI functions which
 	  this kernel will support.
 
-config PCI_NR_MSI
-	int "Maximum number of MSI interrupts (64-32768)"
-	range 64 32768
-	default "256"
-	help
-	  This defines the number of virtual interrupts the kernel will
-	  provide for MSI interrupts. If you configure your system to have
-	  too few drivers will fail to allocate MSI interrupts for all
-	  PCI devices.
-
 source "drivers/pci/Kconfig"
 
 endif	# PCI