Revert "android: enable assembly optimizations for x86_64"

This reverts commit c1eb1178.

Doesn't build.

Change-Id: Id1ec839d9cd0d0ba000ef296c459b9c73413e571

contrib/src/ffmpeg/rules.mak

@@ -110,6 +110,9 @@ endif
 ifeq ($(ARCH),i386)
 FFMPEGCONF += --disable-asm
 endif
+ifeq ($(ARCH),x86_64)
+FFMPEGCONF += --disable-asm
+endif
 else
 # Desktop Linux
 FFMPEGCONF += \