drivers: wifi: eswifi: Fix parsing buffer-overflows

There are possible buffer overflows when parsing the ip address and
SSID. Ensure that we never overwrite the ip and SSID buffers.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>