media: atomisp: unify ia_css_isp_params.c

The contents of ia_css_isp_params.c is almost identical for
2400 and 2401. The only difference is that, on 2400, there
are some duplicated assignments. So, drop it, unifying this
file.

While here, simplify the Makefile's logic by dropping an
unused define.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>