ABI: pstore: Fix What field

If both /sys/fs/pstore/... and /dev/pstore/... are possible,
it should use, instead, two What: fields.
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/e19daafb779bd3a8f9ae1c15f670752355e5d40f.1631782432.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/pstore

-What:		/sys/fs/pstore/... (or /dev/pstore/...)
+What:		/sys/fs/pstore/...
+What:		/dev/pstore/...
 Date:		March 2011
 KernelVersion: 2.6.39
 Contact:	tony.luck@intel.com