Revert "lib: Revert use of fallthrough pseudo-keyword in lib/"

This reverts commit 6a9dc5fd6170 ("lib: Revert use of fallthrough
pseudo-keyword in lib/")

Now that we can build arch/powerpc/boot/ free of -Wimplicit-fallthrough,
re-enable these fixes for lib/.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/236
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
diff --git a/lib/dim/rdma_dim.c b/lib/dim/rdma_dim.c
index f7e26c7..15462d5 100644
--- a/lib/dim/rdma_dim.c
+++ b/lib/dim/rdma_dim.c
@@ -59,7 +59,7 @@ static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
 			break;
 		case DIM_STATS_WORSE:
 			dim_turn(dim);
-			/* fall through */
+			fallthrough;
 		case DIM_STATS_BETTER:
 			step_res = rdma_dim_step(dim);
 			if (step_res == DIM_ON_EDGE)
@@ -94,7 +94,7 @@ void rdma_dim(struct dim *dim, u64 completions)
 			schedule_work(&dim->work);
 			break;
 		}
-		/* fall through */
+		fallthrough;
 	case DIM_START_MEASURE:
 		dim->state = DIM_MEASURE_IN_PROGRESS;
 		dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0,