Move gk20a_init_gr function from gr_gk20a.c to gr.c as nvgpu_gr_init. Update all files that call gk20a_init_gr function. JIRA NVGPU-1885 Change-Id: I318a34778e23a7372be574ee9c21c5b65011e535 Signed-off-by: Vinod G <vinodg@nvidia.com> Reviewed-on: https://git-master.nvidia.com/r/2092648 Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com> Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>