a3xelte: Set SDK API level for rild

* P made changes to pthread_mutex_init() that are incompatible
  with our libsec-ril libraries. In order for rild to even see a
  radio as being availble we need the legacy behavior.
* Even though our libsec-ril libraries are from 7.0, which is API
  level 24, we do not appear to require any of the other behaviors
  from API levels earlier than 27.

Change-Id: I3b3d0160236df09bdae95c5d9f10a61bf91ebc72

BoardConfig.mk

@@ -51,3 +51,7 @@ TARGET_LD_SHIM_LIBS += \
     /system/lib/libcamera_client.so|/vendor/lib/libcamera_client_shim.so \
     /system/lib/libstagefright.so|/vendor/lib/libstagefright_shim.so \
     /system/lib/libexynoscamera.so|/vendor/lib/libexynoscamera_shim.so
+
+# Legacy BLOB Support
+TARGET_PROCESS_SDK_VERSION_OVERRIDE += \
+    /system/vendor/bin/hw/rild=27