Ensure pipe returns 0 if input read/write len is 0
Ensure pipe returns 0 if input read/write len is 0

This commit is from nuttx 7.18(0a939ff218972d517cbca942543e1e45b0d3df76)
Pipes: Fix zero-lenth writes.  From  Jussi Kivilinna

Change-Id: I7f1032f13b72e85c2a23b6540b6371a52c1dd100

sunghan-chang/TizenRT,dr-venkman/TizenRT,chanijjani/TizenRT,HONGCHAEHEE/TizenRT,jeongchanKim/TizenRT,JeongJunSik/TizenRT,JeonginKim/TizenRT,lokeshbv/TizenRT,kimusan/TizenRT,manoharahk/TizenRT,sunghan-chang/TizenRT,jeongarmy/TizenRT,EunBongSong/TizenRT,guswns0528/TizenRT,JunhwanPark/TizenRT,an4967/TizenRT,jeongchanKim/TizenRT,sangwon03/TizenRT,Samsung/TizenRT,youngeunpark/TizenRT,youngeunpark/TizenRT,jsdosa/TizenRT,jeongchanKim/TizenRT,yashwanth686007/TizenRTOS,sangwon03/TizenRT,kimusan/TizenRT,Parkjihooni6186/TizenRT,an4967/TizenRT,JeonginKim/TizenRT,junmin-kim/TizenRT,lssgood/TizenRT,sunghan-chang/TizenRT,sunghan-chang/TizenRT,sangwon03/TizenRT,guswns0528/TizenRT,lokeshbv/TizenRT,Samsung/TizenRT,olegartys/TizenRT,pillip8282/TizenRT,sangwon03/TizenRT,shivgarg/TizenRT,btheosam/TizenRT,shivgarg/TizenRT,heejin-kim/TizenRT,pillip8282/TizenRT,JeonginKim/TizenRT,jsdosa/TizenRT,jsdosa/TizenRT,yashwanth686007/TizenRTOS,JeonginKim/TizenRT,manoharahk/TizenRT,junmin-kim/TizenRT,JeongJunSik/TizenRT,youngeunpark/TizenRT,lssgood/TizenRT,HONGCHAEHEE/TizenRT,EunBongSong/TizenRT,pillip8282/TizenRT,junmin-kim/TizenRT,pillip8282/TizenRT,btheosam/TizenRT,btheosam/TizenRT,junmin-kim/TizenRT,EunBongSong/TizenRT,jeongarmy/TizenRT,Samsung/TizenRT,lokeshbv/TizenRT,JunhwanPark/TizenRT,heejin-kim/TizenRT,davidfather/TizenRT,lokeshbv/TizenRT,jsdosa/TizenRT,pillip8282/TizenRT,chanijjani/TizenRT,youngeunpark/TizenRT,sunghan-chang/TizenRT,heejin-kim/TizenRT,dr-venkman/TizenRT,davidfather/TizenRT,pillip8282/TizenRT,sangwon03/TizenRT,davidfather/TizenRT,dr-venkman/TizenRT,Samsung/TizenRT,sunghan-chang/TizenRT,EunBongSong/TizenRT,olegartys/TizenRT,btheosam/TizenRT,jsdosa/TizenRT,JeongJunSik/TizenRT,yashwanth686007/TizenRTOS,yashwanth686007/TizenRTOS,HONGCHAEHEE/TizenRT,manoharahk/TizenRT,jeongarmy/TizenRT,Samsung/TizenRT,an4967/TizenRT,junmin-kim/TizenRT,shivgarg/TizenRT,HONGCHAEHEE/TizenRT,lssgood/TizenRT,youngeunpark/TizenRT,olegartys/TizenRT,olegartys/TizenRT,an4967/TizenRT,kimusan/TizenRT,yashwanth686007/TizenRTOS,jeongarmy/TizenRT,guswns0528/TizenRT,jeongchanKim/TizenRT,Parkjihooni6186/TizenRT,HONGCHAEHEE/TizenRT,guswns0528/TizenRT,davidfather/TizenRT,heejin-kim/TizenRT,junmin-kim/TizenRT,dr-venkman/TizenRT,youngeunpark/TizenRT,lokeshbv/TizenRT,davidfather/TizenRT,shivgarg/TizenRT,kimusan/TizenRT,jsdosa/TizenRT,lssgood/TizenRT,Parkjihooni6186/TizenRT,manoharahk/TizenRT,an4967/TizenRT,jeongchanKim/TizenRT,EunBongSong/TizenRT,heejin-kim/TizenRT,JunhwanPark/TizenRT,an4967/TizenRT,kimusan/TizenRT,chanijjani/TizenRT,chanijjani/TizenRT,shivgarg/TizenRT,EunBongSong/TizenRT,jeongarmy/TizenRT,davidfather/TizenRT,heejin-kim/TizenRT,JeonginKim/TizenRT,sunghan-chang/TizenRT,lssgood/TizenRT,Parkjihooni6186/TizenRT,JunhwanPark/TizenRT,lssgood/TizenRT,HONGCHAEHEE/TizenRT,JunhwanPark/TizenRT,jsdosa/TizenRT,dr-venkman/TizenRT,JunhwanPark/TizenRT,JeonginKim/TizenRT,lokeshbv/TizenRT,JeongJunSik/TizenRT,jeongchanKim/TizenRT,jeongarmy/TizenRT,guswns0528/TizenRT,Samsung/TizenRT,davidfather/TizenRT,btheosam/TizenRT,olegartys/TizenRT,dr-venkman/TizenRT,pillip8282/TizenRT,manoharahk/TizenRT,jeongarmy/TizenRT,kimusan/TizenRT,btheosam/TizenRT,Samsung/TizenRT,JeongJunSik/TizenRT,chanijjani/TizenRT,shivgarg/TizenRT,chanijjani/TizenRT,Parkjihooni6186/TizenRT,olegartys/TizenRT,manoharahk/TizenRT,yashwanth686007/TizenRTOS,an4967/TizenRT,chanijjani/TizenRT,sangwon03/TizenRT,junmin-kim/TizenRT,Parkjihooni6186/TizenRT,jeongchanKim/TizenRT,JeongJunSik/TizenRT