workflows: Switch to overlaycheck's thorough mode

Now that the current trees are passing the thorough/try-all mode of
overlaycheck (mainly by excluding trying to apply the vl805 overlay
on a CM4S), use it in the build checks.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

Author: pelwell

.github/workflows/dtoverlaycheck.yml

@@ -45,4 +45,4 @@ jobs:
         pwd
         make ARCH=arm KERNEL=kernel CROSS_COMPILE=arm-linux-gnueabihf- bcm2709_defconfig
         make ARCH=arm KERNEL=kernel CROSS_COMPILE=arm-linux-gnueabihf- dtbs
-        ${{env.UTILS_DIR}}/overlaycheck/overlaycheck
+        ${{env.UTILS_DIR}}/overlaycheck/overlaycheck -t