Revert "sanitycheck: deal with board that have no DTS"

PR zephyrproject-rtos#20204 broke master for boards without DTS
PR zephyrproject-rtos#20365 tried to partially fix it, but the filtering in
sanitycheck remained broken
Let's quickly revert it to allow other PRs to come in,
and then resubmit them in a separate PR.

This reverts commit 556f3cb.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

scripts/sanitycheck

@@ -1896,9 +1896,9 @@ class FilterBuilder(CMake):
         filter_data.update(self.defconfig)
         filter_data.update(self.cmake_cache)
 
-        dts_path = os.path.join(self.build_dir, "zephyr", self.platform.name + ".dts.pre.tmp")
-        if self.testcase and self.testcase.tc_filter and os.path.exists(dts_path):
+        if self.testcase and self.testcase.tc_filter:
             try:
+                dts_path = os.path.join(self.build_dir, "zephyr", self.platform.name + ".dts.pre.tmp")
                 edt = edtlib.EDT(dts_path, [os.path.join(ZEPHYR_BASE, "dts", "bindings")])
                 res = expr_parser.parse(self.testcase.tc_filter, filter_data, edt)