nouveau: Add missing break statement

Add the missing break statement that causes the following build error

	  CC [M]  drivers/gpu/drm/i915/display/intel_display_device.o
	../drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c: In function ‘build_registry’:
	../drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1266:3: error: label at end of compound statement
	1266 |   default:
	      |   ^~~~~~~
	  CC [M]  drivers/gpu/drm/amd/amdgpu/gfx_v10_0.o
	  HDRTEST drivers/gpu/drm/xe/compat-i915-headers/i915_reg.h
	  CC [M]  drivers/gpu/drm/amd/amdgpu/imu_v11_0.o
	make[7]: *** [../scripts/Makefile.build:244: drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.o] Error 1
	make[7]: *** Waiting for unfinished jobs....

Fixes: b58a0bc9 ("nouveau: add command-line GSP-RM registry support")
Closes: https://lore.kernel.org/all/913052ca6c0988db1bab293cfae38529251b4594.camel@nvidia.com/T/#m3c9acebac754f2e74a85b76c858c093bb1aacaf0
Closes: https://lore.kernel.org/all/CA+G9fYu7Ug0K8h9QJT0WbtWh_LL9Juc+VC0WMU_Z_vSSPDNymg@mail.gmail.com/Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240430131840.742924-1-chaitanya.kumar.borah@intel.com

drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c

@@ -1264,6 +1264,7 @@ static void build_registry(struct nvkm_gsp *gsp, PACKED_REGISTRY_TABLE *registry
 			str_offset += reg->vlen;
 			break;
 		default:
+			break;
 		}
 
 		i++;