Enable devices to signal interrupts via PCI memory cycles.

rev6:
* fix enable/disable typo, Michael Ellerman

rev5:
* fix up ack, enable, and disable for iop13xx_msi_chip

rev4:
* move smp compile fix to separate patch
* use dynamic_irq_init in create_irq()
* hookup mask/unmask routines in iop13xx_msi_chip

rev3:
* change msi.c to use linux/smp.h instead of asm/smp.h
* call dynamic_irq_cleanup at destroy_irq time

rev2:
* destroy_irq did not take the full 128 bits of msi_irq_in_use into account
* added missing '&' for calls to test_and_set_bit and clear_bit

[ebiederm@xmission.com: review comments/suggestions]
[dan.j.williams@intel.com: cleanups/forward port to 2.6-git]
Signed-off-by: Daniel Wolstenholme <daniel.e.wolstenholme@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>