Remove a few libs used by soft omx from vndk

Soft omx plugins are already removed from vndk,
these should have been removed together. Keeping
them in vndk with have both 32 and 64 bit on system,
but soft omx only uses one set.

bug: 132466615
test: build and check these libs are now on vendor/lib.
Change-Id: I09ce20820ca96d71ddd02a45b68147c8388c841d

media/libstagefright/codecs/amrnb/common/Android.bp

@@ -1,9 +1,6 @@
 cc_library_shared {
     name: "libstagefright_amrnb_common",
     vendor_available: true,
-    vndk: {
-        enabled: true,
-    },
 
     srcs: [
         "src/add.cpp",

media/libstagefright/codecs/common/Android.bp

@@ -1,9 +1,6 @@
 cc_library {
     name: "libstagefright_enc_common",
     vendor_available: true,
-    vndk: {
-        enabled: true,
-    },
 
     srcs: ["cmnMemory.c"],
 

media/libstagefright/flac/dec/Android.bp

@@ -1,9 +1,6 @@
 cc_library {
     name: "libstagefright_flacdec",
     vendor_available: true,
-    vndk: {
-        enabled: true,
-    },
 
     srcs: [
         "FLACDecoder.cpp",