samples: mbedTLS coap: Cleaning prj.conf for QEMU
samples: mbedTLS coap: Cleaning prj.conf for QEMU

Removing unneeded configuration

Change-Id: I72e3714358366de715cb6f47d690a1b0e8f032f5
Signed-off-by: Sergio Rodriguez <9789aa5c5c93f909016928416139ed4e6b9138f3@intel.com>

fbsder/zephyr,fbsder/zephyr,fbsder/zephyr,fbsder/zephyr,fbsder/zephyr