media: staging: media: atomisp: fix stack overflow in init_pipe_defaults()

When building with clang, multiple copies of the structures to be
initialized are passed around on the stack and copied locally, using an
insane amount of stack space:

drivers/staging/media/atomisp/pci/sh_css.c:2371:1: error: stack frame size of 26864 bytes in function 'create_pipe' [-Werror,-Wframe-larger-than=]

Use constantly-allocated variables plus an explicit memcpy()
to avoid that.

Co-authored-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Fixes: 6dc9a2568f84 ("media: atomisp: convert default struct values to use compound-literals with designated initializers")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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: 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>