.travis.yml: test xtensa xtfpga board in QEMU

This allows running tests on emulated KC705 board with DC233C xtensa
core. It expects to find conf.xtfpga_qemu in the uboot-test-hooks.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

.travis.yml

@@ -388,5 +388,12 @@ matrix:
           QEMU_TARGET="arm-softmmu"
           TEST_PY_ID="--id qemu"
           BUILDMAN="^zynq_zc702$"
+    - env:
+        - TEST_PY_BD="xtfpga"
+          TEST_PY_TEST_SPEC="not sleep"
+          QEMU_TARGET="xtensa-softmmu"
+          TEST_PY_ID="--id qemu"
+          BUILDMAN="^xtfpga$"
+          TOOLCHAIN="xtensa-dc233c-elf"
 
 # TODO make it perfect ;-r