media: MAINTAINERS: adjust entry to refactoring smiapp.h

Commit 7cbeb2e1 ("media: smiapp: Move definitions under driver
directory") moved the definitions in include/media/i2c/smiapp.h into other
files and removed include/media/i2c/smiapp.h.

Since then, ./scripts/get_maintainer.pl --self-test complains:

  warning: no file matches F: include/media/i2c/smiapp.h

Remove MAINTAINER file entry to this removed file and while at it, update
Sakari's email address in this section.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>