iio:max1363 remove some functions left after merge

merge commit 17cb3be6
seems to have resulted in two functions that were removed in
4389fbec reappearing.

Spotted due to a build kicking out

drivers/iio/adc/max1363.c:1486:12: warning: 'max1363_register_buffered_funcs_and_init' defined but not used
drivers/iio/adc/max1363.c:1521:13: warning: 'max1363_buffer_cleanup' defined but not used

This patch just removes them again.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>