[POWREPC] Fixup a number of modpost warnings on ppc32

Fixed the following warnings:

WARNING: vmlinux.o(.text+0x2934): Section mismatch: reference to .init.text:__alloc_bootmem (between 'irq_alloc_host' and 'irq_set_default_host')
WARNING: vmlinux.o(.text+0xb2aa): Section mismatch: reference to .init.data:boot_command_line (between 'register_early_udbg_console' and 'udbg_printf')
WARNING: vmlinux.o(.text+0xb2b2): Section mismatch: reference to .init.data:boot_command_line (between 'register_early_udbg_console' and 'udbg_printf')
WARNING: vmlinux.o(.text+0xe354): Section mismatch: reference to .init.text:__alloc_bootmem (between 'pcibios_alloc_controller' and 'pci_domain_nr')
WARNING: vmlinux.o(.text+0x12768): Section mismatch: reference to .init.text:update_bridge_resource (between 'quirk_fsl_pcie_transparent' and 'indirect_read_config')
WARNING: vmlinux.o(.text+0x127a8): Section mismatch: reference to .init.text:update_bridge_resource (between 'quirk_fsl_pcie_transparent' and 'indirect_read_config')
WARNING: vmlinux.o(.text+0x17566c): Section mismatch: reference to .init.text:pcibios_fixup_bus (between 'pci_scan_child_bus' and 'pci_scan_bus_parented')

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 2fc8786..24bea97 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -418,10 +418,10 @@
 }
 EXPORT_SYMBOL_GPL(virq_to_hw);
 
-struct irq_host *irq_alloc_host(unsigned int revmap_type,
-				unsigned int revmap_arg,
-				struct irq_host_ops *ops,
-				irq_hw_number_t inval_irq)
+__init_refok struct irq_host *irq_alloc_host(unsigned int revmap_type,
+						unsigned int revmap_arg,
+						struct irq_host_ops *ops,
+						irq_hw_number_t inval_irq)
 {
 	struct irq_host *host;
 	unsigned int size = sizeof(struct irq_host);