Don't depend on String8 cast to C string [cas]

Bug: 295394788
Test: m checkbuild
Change-Id: I82c94f0a720957c443f92b030214c6d2c47bf009
diff --git a/cas/aidl/default/DescramblerImpl.cpp b/cas/aidl/default/DescramblerImpl.cpp
index d658887..0f4e99b 100644
--- a/cas/aidl/default/DescramblerImpl.cpp
+++ b/cas/aidl/default/DescramblerImpl.cpp
@@ -71,7 +71,7 @@
         *_aidl_return = false;
     }
 
-    *_aidl_return = holder->requiresSecureDecoderComponent(String8(in_mime.c_str()));
+    *_aidl_return = holder->requiresSecureDecoderComponent(in_mime.c_str());
     return ScopedAStatus::ok();
 }