libdts: Support non-static DTC

Fall back to 'dtc' when 'dtc_static' is not available e.g. when running
tests on the (ADB) host.

Test: - # ToT doesn't currently support host-side tests using libdts
Flag: EXEMPT tests
Change-Id: I648e91e363156093ab802b9b11b59de8d94a5b61
diff --git a/tests/libs/libdts/src/lib.rs b/tests/libs/libdts/src/lib.rs
index d6b90f7..273cae5 100644
--- a/tests/libs/libdts/src/lib.rs
+++ b/tests/libs/libdts/src/lib.rs
@@ -76,9 +76,12 @@
 
     fn get_dtc() -> Option<Command> {
         const DTC_STATIC: &str = "./dtc_static";
+        const DTC: &str = "./dtc";
 
         if Path::new(DTC_STATIC).exists() {
             Some(Command::new(DTC_STATIC))
+        } else if Path::new(DTC).exists() {
+            Some(Command::new(DTC))
         } else {
             None
         }