x86/mm/pat: Fix typo in the Kconfig help text

Signed-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/Kconfig

@@ -1512,7 +1512,7 @@ config X86_CPA_STATISTICS
 	bool "Enable statistic for Change Page Attribute"
 	depends on DEBUG_FS
 	---help---
-	  Expose statistics about the Change Page Attribute mechanims, which
+	  Expose statistics about the Change Page Attribute mechanism, which
 	  helps to determine the effectiveness of preserving large and huge
 	  page mappings when mapping protections are changed.