driver core: fix up some missing class.devnode() conversions.

driver core: fix up some missing class.devnode() conversions.

In commit ff62b8e6588f ("driver core: make struct class.devnode() take a
const *") the ->devnode callback changed the pointer to be const, but a
few instances of PowerPC drivers were not caught for some reason.

Fix this up by changing the pointers to be const.

Fixes: ff62b8e6588f ("driver core: make struct class.devnode() take a const *")
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Frederic Barrat <fbarrat@linux.ibm.com>
Cc: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linuxppc-dev@lists.ozlabs.org
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/r/20221128173539.3112234-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>