iommu/amd: Remove unused forward declaration

Remove unused forward declaration.

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20250227162320.5805-7-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd/init.c

@@ -219,7 +219,6 @@ static bool __initdata cmdline_maps;
 static enum iommu_init_state init_state = IOMMU_START_STATE;
 
 static int amd_iommu_enable_interrupts(void);
-static int __init iommu_go_to_state(enum iommu_init_state state);
 static void init_device_table_dma(struct amd_iommu_pci_seg *pci_seg);
 
 static bool amd_iommu_pre_enabled = true;