Remove lock on MediaCrypto's decrypt call

The lock isn't necessary and prevents concurrent hwbinder
calls into the drm plugin which impacts performance.
Serialization of decrypt calls is done at a lower level.

bug: 157017229
test: Media GTS tests on coral
Change-Id: I38e3132f45c140cba9b2b8a72054fbff5eedb997
diff --git a/drm/libmediadrm/CryptoHal.cpp b/drm/libmediadrm/CryptoHal.cpp
index 18772e0..4bfa12b 100644
--- a/drm/libmediadrm/CryptoHal.cpp
+++ b/drm/libmediadrm/CryptoHal.cpp
@@ -376,6 +376,7 @@
 
     Return<void> hResult;
 
+    mLock.unlock();
     if (mPluginV1_2 != NULL) {
         hResult = mPluginV1_2->decrypt_1_2(secure, toHidlArray16(keyId), toHidlArray16(iv),
                 hMode, hPattern, hSubSamples, hSource, offset, hDestination,