staging: atomisp: satm include directory is gone

After the satm kernel was removed, we should no longer add the directory
to the search path. This was found with a 'make W=1' warning:

cc1: error: drivers/staging/media/atomisp/pci/atomisp2/css2400/isp/kernels/satm/: No such file or directory [-Werror=missing-include-dirs]

Fixes: 184f8e09 ("atomisp: remove satm kernel")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>