drm/nouveau/bios/timing: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 1260018
Addresses-Coverity-ID: 1260019
Addresses-Coverity-ID: 1260022
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/subdev/bios/timing.c

@@ -115,16 +115,21 @@ nvbios_timingEp(struct nvkm_bios *bios, int idx,
 		switch (min_t(u8, *hdr, 25)) {
 		case 25:
 			p->timing_10_24  = nvbios_rd08(bios, data + 0x18);
+			/* fall through */
 		case 24:
 		case 23:
 		case 22:
 			p->timing_10_21  = nvbios_rd08(bios, data + 0x15);
+			/* fall through */
 		case 21:
 			p->timing_10_20  = nvbios_rd08(bios, data + 0x14);
+			/* fall through */
 		case 20:
 			p->timing_10_CWL = nvbios_rd08(bios, data + 0x13);
+			/* fall through */
 		case 19:
 			p->timing_10_18  = nvbios_rd08(bios, data + 0x12);
+			/* fall through */
 		case 18:
 		case 17:
 			p->timing_10_16  = nvbios_rd08(bios, data + 0x10);