x86/mm/pat: Fix W=1 build kernel-doc warning

Building the kernel with W=1 generates the following warning:

  arch/x86/mm/pat/memtype.c:692: warning: Function parameter or struct member 'pfn' not described in 'pat_pfn_immune_to_uc_mtrr'

Add missing parameter documentation to fix the kernel-doc warning.

Signed-off-by: Shivank Garg <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: shivankgarg98

arch/x86/mm/pat/memtype.c

@@ -682,6 +682,7 @@ static enum page_cache_mode lookup_memtype(u64 paddr)
 /**
  * pat_pfn_immune_to_uc_mtrr - Check whether the PAT memory type
  * of @pfn cannot be overridden by UC MTRR memory type.
+ * @pfn: The page frame number to check.
  *
  * Only to be called when PAT is enabled.
  *