Fixed a couple of issues in the FSR 2.2 shader sources

Assets/Resources/FSR2/shaders/ffx_fsr2_callbacks_hlsl.h

@@ -508,6 +508,11 @@ void StoreLumaHistory(FfxUInt32x2 iPxPos, FfxFloat32x4 fLumaHistory)
 {
     rw_luma_history[iPxPos] = fLumaHistory;
 }
+
+FfxFloat32x4 LoadRwLumaHistory(FFX_MIN16_I2 iPxPos)
+{
+    return rw_luma_history[iPxPos];
+}
 #endif
 
 #if defined(FSR2_BIND_SRV_LUMA_HISTORY) || defined(FFX_INTERNAL)

Assets/Resources/FSR2/shaders/ffx_fsr2_prepare_input_color_pass.hlsl

@@ -28,7 +28,7 @@
 // CB   0 : cbFSR2
 
 #define FSR2_BIND_SRV_INPUT_COLOR                           0
-#define FSR2_BIND_SRV_EXPOSURE                              1
+#define FSR2_BIND_SRV_INPUT_EXPOSURE                        1
 #define FSR2_BIND_UAV_RECONSTRUCTED_PREV_NEAREST_DEPTH      0
 #define FSR2_BIND_UAV_PREPARED_INPUT_COLOR                  1
 #define FSR2_BIND_UAV_LUMA_HISTORY                          2