MAINTAINERS: Fix 'W:' prefix in Invensense IMU entry

The colon is missing, which can confuse scripts/parse-maintainers.pl.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20201108013738.1410528-1-j.neuschaefer@gmx.net


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