iommu/amd: Fix typo in kernel-parameters.txt

Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a0c5c5f..da50377 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -320,7 +320,7 @@
 			on: enable for both 32- and 64-bit processes
 			off: disable for both 32- and 64-bit processes
 
-	amd_iommu=	[HW,X86-84]
+	amd_iommu=	[HW,X86-64]
 			Pass parameters to the AMD IOMMU driver in the system.
 			Possible values are:
 			fullflush - enable flushing of IO/TLB entries when