JPEG/R refactor: rename "recovery map" to "gain map"

Bug: b/264715926
Test: build, jpegr_test, gainmapmath_test
Change-Id: I9ff07ed4201f0d7ee664209fc0450808f2ec143d
diff --git a/libs/jpegrecoverymap/Android.bp b/libs/jpegrecoverymap/Android.bp
index a1b0e19..a376ced 100644
--- a/libs/jpegrecoverymap/Android.bp
+++ b/libs/jpegrecoverymap/Android.bp
@@ -31,7 +31,7 @@
     srcs: [
         "icc.cpp",
         "jpegr.cpp",
-        "recoverymapmath.cpp",
+        "gainmapmath.cpp",
         "jpegrutils.cpp",
         "multipictureformat.cpp",
     ],