iommu/amd: Wrap debugfs ABI testing symbols snippets in literal code blocks

iommu/amd: Wrap debugfs ABI testing symbols snippets in literal code blocks

Commit 39215bb3b0d929 ("iommu/amd: Add documentation for AMD IOMMU
debugfs support") documents debugfs ABI symbols for AMD IOMMU, but
forgets to wrap examples snippets and their output in literal code
blocks, hence Sphinx reports indentation warnings:

Documentation/ABI/testing/debugfs-amd-iommu:31: ERROR: Unexpected indentation. [docutils]
Documentation/ABI/testing/debugfs-amd-iommu:31: WARNING: Block quote ends without a blank line; unexpected unindent. [docutils]
Documentation/ABI/testing/debugfs-amd-iommu:31: WARNING: Block quote ends without a blank line; unexpected unindent. [docutils]

Wrap them to fix the warnings.

Fixes: 39215bb3b0d9 ("iommu/amd: Add documentation for AMD IOMMU debugfs support")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20250716204207.73869849@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20250717010331.8941-1-bagasdotme@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>