InputDevice: return std::optional from getAbsoluteAxisInfo

This also allows us to remove the valid field from RawAbsoluteAxisInfo,
since we can represent "invalid" axes (which usually just meant absent
ones) using std::nullopt.

Test: atest inputflinger_tests
Test: m checkinput
Test: Check "Raw Touch Axes" section of touch input mapper info in
      dumpsys input
Bug: 245989146
Flag: EXEMPT refactor
Change-Id: I045a2e0b61a84657f2f8171c1fee3cc3e331ac86
diff --git a/services/inputflinger/reader/mapper/JoystickInputMapper.cpp b/services/inputflinger/reader/mapper/JoystickInputMapper.cpp
index 41e018d..3091714 100644
--- a/services/inputflinger/reader/mapper/JoystickInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/JoystickInputMapper.cpp
@@ -117,9 +117,8 @@
                 continue; // axis must be claimed by a different device
             }
 
-            RawAbsoluteAxisInfo rawAxisInfo;
-            getAbsoluteAxisInfo(abs, &rawAxisInfo);
-            if (rawAxisInfo.valid) {
+            if (std::optional<RawAbsoluteAxisInfo> rawAxisInfo = getAbsoluteAxisInfo(abs);
+                rawAxisInfo) {
                 // Map axis.
                 AxisInfo axisInfo;
                 const bool explicitlyMapped = !getDeviceContext().mapAxis(abs, &axisInfo);
@@ -129,7 +128,7 @@
                     axisInfo.mode = AxisInfo::MODE_NORMAL;
                     axisInfo.axis = -1;
                 }
-                mAxes.insert({abs, createAxis(axisInfo, rawAxisInfo, explicitlyMapped)});
+                mAxes.insert({abs, createAxis(axisInfo, rawAxisInfo.value(), explicitlyMapped)});
             }
         }