Switch to using the private watchdog as the run time stats timer in the Zynq demo.

git-svn-id: http://svn.code.sf.net/p/freertos/code/trunk@2255 1d2547de-c912-0410-9cb9-b8ca96c0e9e2
Remove some of the lwip asserts to allow use with 64-bit alignment.

git-svn-id: http://svn.code.sf.net/p/freertos/code/trunk@2256 1d2547de-c912-0410-9cb9-b8ca96c0e9e2