Documentation/features/vm: correct huge-vmap APIs

Documentation/features/vm: correct huge-vmap APIs

In commit:

  bbc180a5adb05ee8 ("mm: HUGE_VMAP arch support cleanup")

We replaced:

  * ioremap_pud_enabled() with arch_vmap_pud_supported()
  * ioremap_pmd_enabled() with arch_vmap_pmd_supported()

Update the documentation accordingly.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20210817091621.16799-1-mark.rutland@arm.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>