Remove unused code from midi engine

Bug: 151448144
Test: build, CTS
Change-Id: Id8952cd036052d7f7ca71e5cedbc24f7ae2c852b

Author: marcone

arm-wt-22k/Android.bp

@@ -1,13 +1,9 @@
 cc_library {
     name: "libsonivox",
     srcs: [
-        "lib_src/eas_chorus.c",
-        "lib_src/eas_chorusdata.c",
         "lib_src/eas_data.c",
         "lib_src/eas_dlssynth.c",
         "lib_src/eas_flog.c",
-        "lib_src/eas_ima_tables.c",
-        "lib_src/eas_imaadpcm.c",
         "lib_src/eas_imelody.c",
         "lib_src/eas_imelodydata.c",
         "lib_src/eas_math.c",
@@ -38,12 +34,6 @@ cc_library {
         "host_src/eas_config.c",
         "host_src/eas_hostmm.c",
         "host_src/eas_report.c",
-
-        // not using these modules
-        //"host_src/eas_main.c",
-        //"host_src/eas_wave.c",
-        //"lib_src/eas_wavefile.c",
-        //"lib_src/eas_wavefiledata.c",
     ],
 
     cflags: [