Zynq demo:  Fix Xilinx network driver by deferring the function that allocated memory from the interrupt into a task.  Add DHCP option.

git-svn-id: http://svn.code.sf.net/p/freertos/code/trunk@2257 1d2547de-c912-0410-9cb9-b8ca96c0e9e2
Added portASSERT_IF_IN_INTERRUPT() macro to the GCC Cortex A9 port layer.

git-svn-id: http://svn.code.sf.net/p/freertos/code/trunk@2258 1d2547de-c912-0410-9cb9-b8ca96c0e9e2