aaudio: fix ramp for volume smoothing

It was using numSamples instead of numFrames.
So timing was off.

Bug: 68804159
Test: raise and lower volume without clicking
Test: test_linear_ramp.cpp
Change-Id: I18b10dadbc47ab9cbe9c5aefd4e6197c50a0bedc
diff --git a/media/libaaudio/src/utility/LinearRamp.h b/media/libaaudio/src/utility/LinearRamp.h
index ff09dce..2b1b8e0 100644
--- a/media/libaaudio/src/utility/LinearRamp.h
+++ b/media/libaaudio/src/utility/LinearRamp.h
@@ -87,7 +87,7 @@
 
     std::atomic<float>   mTarget;
 
-    int32_t mLengthInFrames  = 48000 / 50; // 20 msec at 48000 Hz
+    int32_t mLengthInFrames  = 48000 / 100; // 10 msec at 48000 Hz
     int32_t mRemaining       = 0;
     float   mLevelFrom       = 0.0f;
     float   mLevelTo         = 0.0f;