x86/irq: Clean up unused forward declarations in x86_init.h

Clean up unused forward declarations in x86_init.h.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Tested-by: Joerg Roedel <jroedel@suse.de>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Link: http://lkml.kernel.org/r/1428978610-28986-9-git-send-email-jiang.liu@linux.intel.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/x86_init.h

@@ -171,7 +171,6 @@ struct x86_platform_ops {
 };
 
 struct pci_dev;
-struct msi_msg;
 
 struct x86_msi_ops {
 	int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
@@ -180,11 +179,6 @@ struct x86_msi_ops {
 	void (*restore_msi_irqs)(struct pci_dev *dev);
 };
 
-struct IO_APIC_route_entry;
-struct io_apic_irq_attr;
-struct irq_data;
-struct cpumask;
-
 struct x86_io_apic_ops {
 	void		(*init)   (void);
 	unsigned int	(*read)   (unsigned int apic, unsigned int reg);