DHCP network buffers (#107)

* Repair FreeRTOS_SendPingRequest

* uxGetNumberOfFreeNetworkBuffers() should return 4 or more

* DHCP: call pxGetNetworkBufferWithDescriptor in a polling way

* Added a word to lexicon.txt

* And corrected some typo's

* Corrected one more typo and ran Uncrustify again

* Grammar change.

Co-authored-by: Hein Tibosch <[email protected]>
Co-authored-by: Aniruddha Kanhere <[email protected]>

Author: 3 people

.github/lexicon.txt

@@ -252,6 +252,7 @@ ereturned
 ereturnethernetframe
 errbuf
 errno
+esenddhcprequest
 esocketbindevent
 esocketcloseevent
 esocketselectevent