Revert "sanitycheck: remove import of dt kconfig symbols"

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 9b5720d.

Signed-off-by: Alberto Escolar Piedras <alpi@oticon.com>

scripts/sanitycheck

@@ -1720,6 +1720,7 @@ class CMake():
 
         self.defconfig = {}
         self.cmake_cache = {}
+        self.devicetree = {}
 
         self.instance = None
         self.testcase = testcase
@@ -1862,7 +1863,10 @@ class FilterBuilder(CMake):
         if self.platform.name == "unit_testing":
             return {}
 
+        _generated_dt_confg = "include/generated/generated_dts_board.conf"
+
         cmake_cache_path = os.path.join(self.build_dir, "CMakeCache.txt")
+        dt_config_path = os.path.join(self.build_dir, "zephyr", _generated_dt_confg)
         defconfig_path = os.path.join(self.build_dir, "zephyr", ".config")
 
         with open(defconfig_path, "r") as fp:
@@ -1888,13 +1892,26 @@ class FilterBuilder(CMake):
 
         self.cmake_cache = cmake_conf
 
+        dt_conf = {}
+        if os.path.exists(dt_config_path):
+            with open(dt_config_path, "r") as fp:
+                for line in fp.readlines():
+                    m = self.dt_re.match(line)
+                    if not m:
+                        if line.strip() and not line.startswith("#"):
+                            sys.stderr.write("Unrecognized line %s\n" % line)
+                        continue
+                    dt_conf[m.group(1)] = m.group(2).strip()
+        self.devicetree = dt_conf
+
         filter_data = {
             "ARCH": self.platform.arch,
             "PLATFORM": self.platform.name
         }
         filter_data.update(os.environ)
         filter_data.update(self.defconfig)
         filter_data.update(self.cmake_cache)
+        filter_data.update(self.devicetree)
 
         if self.testcase and self.testcase.tc_filter:
             try: