media: atomisp: Mark ia_css_isys_240?_init() static

ia_css_isys_240?_init() are only used inside the C file where they are
declared, mark them as static fixing:

drivers/staging/media/atomisp/pci/runtime/isys/src/isys_init.c:24:20:
warning: no previous prototype for 'ia_css_isys_2400_init'
24 | input_system_err_t ia_css_isys_2400_init(void)
| ^~~~~~~~~~~~~~~~~~~~~
drivers/staging/media/atomisp/pci/runtime/isys/src/isys_init.c:87:20:
warning: no previous prototype for 'ia_css_isys_2401_init'
87 | input_system_err_t ia_css_isys_2401_init(void)
| ^~~~~~~~~~~~~~~~~~~~~

Closes: https://lore.kernel.org/oe-kbuild-all/202307152046.rvhFGrbz-lkp@intel.com/
Link: https://lore.kernel.org/r/20230715170906.3627-3-hdegoede@redhat.com

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Kate Hsuan <hpa@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: atomisp: isys_init: Initiate atomisp in a generic manner

The original implementation distinguishes and initiates atomisp during
compiler time. This commit allows isys_init to initiate isys for both types
of atomisp in a generic manner.

Link: https://lore.kernel.org/r/20230713100231.308923-12-hpa@redhat.com

Signed-off-by: Kate Hsuan <hpa@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: atomisp: unify INPUT error return type

There is a typedef for INPUT errors. This is different between
ISP2401 and ISP2400. Place both at the same struct, at the
global header file.

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

media: atomisp: get rid of isys_dma.h and isys_dma_local.h

There aren't much on this abstraction. Just move the defines
to isys_dma_private.h and isys_dma_public.h, cleaning up
the includes.

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

media: atomisp: get rid of version-dependent globals

Replace all occurrences along the atomisp tree for the conditional
compilation macros found at system_global.h, replacing them by
tests wheather ISP2401 is defined or not.

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

media: atomisp: get rid of some unused code

Now that the defines which are common for both ISP2400 and ISP2401
are at system_global.h, we can get rid of the code not used by
those versions.

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

media: atomisp: add SPDX headers

This driver is licensed under GPL 2.0, as stated inside their
headers.

Add the proper tag there. We should probably latter cleanup
the reduntant licensing text, but this could be done later,
after we get rid of other abstraction layers.

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

media: atomisp: get rid of most checks for ISP2401 version

There are lots of places inside this driver checking for
ISP2400/ISP2401 verison. Get rid of most of those, while
keep building for both.

Most of stuff in this patch is trivial to solve.

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

media: atomisp: cleanup directory hierarchy

This driver has very long directories without a good
reason (IMHO). Let's drop two directories from such hierarchy,
in order to simplify things a little bit and make the dir
output a bit more readable.

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