cmd: blk: remove unreachable code

Remove an unreachable return statement.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/cmd/blk_common.c b/cmd/blk_common.c
index 0c0c23e..bf2f626 100644
--- a/cmd/blk_common.c
+++ b/cmd/blk_common.c
@@ -95,8 +95,6 @@
 		} else {
 			return CMD_RET_USAGE;
 		}
-
-		return 0;
 	}
 }
 #endif