macintosh/ams: Adapt declaration of ams_i2c_remove() to earlier change

Commit ed5c2f5f ("i2c: Make remove callback return void") changed
the prototype of ams_i2c_remove() but failed to adapt the declaration.
Catch up and fix the declaration accordingly.

Fixes: ed5c2f5f ("i2c: Make remove callback return void")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Wolfram Sang <wsa@kernel.org>