Revert "nvmem: core: remove nvmem_config wp_gpio"

This reverts commit 89991ede which is
commit 569653f0 upstream.

It breaks the Android kernel api, and isn't even really needed in the
5.10.y kernel tree yet, as there are no users of the new field.  So
revert it for now.  If it is needed, it can be brought back in an
abi-safe way in the future.

Bug: 161946584
Change-Id: Ib69df930ea19f91d0d35d792e3b90dc1d391980b
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>