gpu: nvgpu: rework ecc structure and sysfs

- create common file common/ecc.c which include common functions for add
  ecc counters and remove counters.
- common code will create a list of all counter which make it easier to
  iterate all counters.
- Add chip specific file for adding ecc counters.
- add linux specific file os/linux/ecc_sysfs.c to export counters to
  sysfs.
- remove obsolete code
- MISRA violation for using snprintf is not solved, tracking with
  jira NVGPU-859

Jira NVGPUT-115

Change-Id: I1905c43c5c9b2b131199807533dee8e63ddc12f4
Signed-off-by: Richard Zhao <rizhao@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1763536
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/os/linux/os_linux.h

@@ -141,6 +141,7 @@ struct nvgpu_os_linux {
 	struct dentry *debugfs_dump_ctxsw_stats;
 #endif
 	DECLARE_HASHTABLE(ecc_sysfs_stats_htable, 5);
+	struct dev_ext_attribute *ecc_attrs;
 
 	struct gk20a_cde_app cde_app;