nshlib/cmd_dd: Retry if read() was interrupted

[JianyuWang0623]

Summary

nshlib/cmd_dd: Retry if read() was interrupted

• Without this patch

nsh> ls /etc/group | dd | dd
sh [13:100]
sh [14:100]
nsh: dd: read failed: 4
nsh>

• With this patch

nsh> ls | dd | dd | dd | dd | dd
sh [4:100]
sh [5:100]
sh [6:100]
sh [7:100]
sh [8:100]
/:
 bin/
 dev/
 etc/
 proc/
 tmp/
 var/
nsh>

Link: #2833 (same reason), #2737 (nsh pipeline)

Impact

nshlib/cmd_dd

Testing

• nsh:sim with pipeline enabled
• NuttX CI