media: staging: media: atomisp: remove pointless string copy

gcc-8 points out that a string is copied to itself here:

In file included from drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/platform_support.h:25,
                 from drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/memory_access/memory_access.h:48,
                 from drivers/staging/media/atomisp/pci/atomisp2/css2400/runtime/debug/src/ia_css_debug.c:16:
In function 'strncpy',
    inlined from 'ia_css_debug_pipe_graph_dump_stage' at drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/string_support.h:158:2:
include/linux/string.h:253:9: error: '__builtin_strncpy' source argument is the same as destination [-Werror=restrict]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This removes the bogus code, leaving the behavior otherwise
unchanged.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>