media: atomisp: fix gcc warnings

Depending on the gcc version, after changeset
72a9ff3b ("media: atomisp: get rid of -Wsuggest-attribute=format warnings"),
we're now getting two warnings, which are breaking the Jenkins
CI instance at https://builder.linuxtv.org:

	../drivers/staging/media/atomisp/pci/atomisp_compat_css20.c: In function ‘__set_css_print_env’:
	../drivers/staging/media/atomisp/pci/atomisp_compat_css20.c:860:50: error: assignment to ‘int (*)(const char *, char *)’ from incompatible pointer type ‘int (__attribute__((regparm(0))) *)(const char *, char *)’ [-Werror=incompatible-pointer-types]
	   isp->css_env.isp_css_env.print_env.debug_print = vprintk;
	                                                  ^
	../drivers/staging/media/atomisp/pci/atomisp_compat_css20.c: In function ‘atomisp_css_load_firmware’:
	../drivers/staging/media/atomisp/pci/atomisp_compat_css20.c:893:49: error: assignment to ‘int (*)(const char *, char *)’ from incompatible pointer type ‘int (__attribute__((regparm(0))) *)(const char *, char *)’ [-Werror=incompatible-pointer-types]
	  isp->css_env.isp_css_env.print_env.error_print = vprintk;
                                                 ^
	cc1: some warnings being treated as errors

So, we need to partially revert the patch.

Fixes: 72a9ff3b

 ("media: atomisp: get rid of -Wsuggest-attribute=format warnings")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>