iio/adc: ingenic: remove unneeded semicolon

A semicolon is not needed after a switch statement.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20201027201128.1597230-1-trix@redhat.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>