iommu/amd: Fix section mismatch warning for detect_ivrs()

A recent commit introduced this section mismatch warning:

	WARNING: modpost: vmlinux.o(.text.unlikely+0x22a1f): Section mismatch in reference from the function detect_ivrs() to the variable .init.data:amd_iommu_force_enable

The reason is that detect_ivrs() is not marked __init while it should
be, because it is only called from another __init function. Mark
detect_ivrs() __init to get rid of the warning.

Fixes: b1e650db2c ("iommu/amd: Add amd_iommu=force_enable option")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20210608122843.8413-1-joro@8bytes.org

drivers/iommu/amd/init.c

@@ -2818,7 +2818,7 @@ out:
 	return ret;
 }
 
-static bool detect_ivrs(void)
+static bool __init detect_ivrs(void)
 {
 	struct acpi_table_header *ivrs_base;
 	acpi_status status;