docs: arm: asymmetric-32bit: Allow creating cross-references for ABI

Now that Documentation/ABI is processed by automarkup, let it
generate cross-references for the corresponding ABI file.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/0a989eea90e5d03a36a07760f8b505e074e85c03.1739254867.git.mchehab+huawei@kernel.org

Author: mchehab

Documentation/arch/arm64/asymmetric-32bit.rst

@@ -55,7 +55,7 @@ sysfs
 
 The subset of CPUs capable of running 32-bit tasks is described in
 ``/sys/devices/system/cpu/aarch32_el0`` and is documented further in
-``Documentation/ABI/testing/sysfs-devices-system-cpu``.
+Documentation/ABI/testing/sysfs-devices-system-cpu.
 
 **Note:** CPUs are advertised by this file as they are detected and so
 late-onlining of 32-bit-capable CPUs can result in the file contents