InputMapper refactor: Change readerconfig pointer to const ref

We are refactoring Input-mapper to ensure they are configured at the
time of initialisation.

In this CL we are changing InputReaderConfiguration raw pointer to
a const reference and rename it to readerConfig for clarity.

Test: build, inputflinger_tests, presubmit checks

Bug: 256009910
Change-Id: Iae22c8cfba836bd311a51fca13d680456a61e604
diff --git a/services/inputflinger/reader/mapper/JoystickInputMapper.cpp b/services/inputflinger/reader/mapper/JoystickInputMapper.cpp
index f60035b..3e840ee 100644
--- a/services/inputflinger/reader/mapper/JoystickInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/JoystickInputMapper.cpp
@@ -104,7 +104,7 @@
 }
 
 std::list<NotifyArgs> JoystickInputMapper::reconfigure(nsecs_t when,
-                                                       const InputReaderConfiguration* config,
+                                                       const InputReaderConfiguration& config,
                                                        uint32_t changes) {
     std::list<NotifyArgs> out = InputMapper::reconfigure(when, config, changes);