media: atomisp: move a static constant out of a header file

Gcc reports that input_formatter_alignment is not used:

	In file included from ./drivers/staging/media/atomisp//pci/hive_isp_css_include/input_formatter.h:34,
	                 from drivers/staging/media/atomisp//pci/runtime/debug/src/ia_css_debug.c:55:
	./drivers/staging/media/atomisp//pci/hive_isp_css_common/host/input_formatter_local.h:118:27: warning: ‘input_formatter_alignment’ defined but not used [-Wunused-const-variable=]

However, it is, but only inside input_formatter.c.

So, move it out of the header file.

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