media: imx: imx7_mipi_csis: convert some switch cases to the default

Static analysis reports this false positive
imx7-mipi-csis.c:1027:2: warning: 4th function call argument is
  an uninitialized value

The variable 'align' is falsely reported as uninitialized.
Even though all the cases are covered in the
	switch (csis_fmt->width % 8) {

Because there is no default case, it is reported as uninialized.

Improve the switch by converting the most numerous set of cases
to the default and silence the false positive.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>