media: atomisp: Fix spelling mistakes in circbuf.c

codespell reported following spelling mistakes
in circbuf.c as below:

'''
./circbuf.c:27: whehter ==> whether
./circbuf.c:132: offest ==> offset
'''
This patch fixes these spelling mistakes.

Link: https://lore.kernel.org/r/20231223060422.77789-1-kdipendra88@gmail.com

Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: atomisp: Remove redundant assignments to variables

There are several variables that are being initialized with values
that are never read, the assignment are redundant and can be removed.
Cleans up cppcheck unreadVariable warnings.

Link: https://lore.kernel.org/r/20231219143929.367929-1-colin.i.king@gmail.com

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@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>