Create gk20a_init_inst_block() to reduce reg write clutter when initializing instance blocks, which is done in several places. Change-Id: Idcb8b604851a849e0bb6abce5743c9f4cbf98033 Signed-off-by: Konsta Holtta <kholtta@nvidia.com> Reviewed-on: http://git-master/r/672434 Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com> Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>