Move the atom optimization flags into TARGET_linux-x86.mk.

Setting libc_crt_target_cflags to be non-recursive is necessary.

Change-Id: I5310d86e705f23da126c21ecb33a97a074da584a
diff --git a/libc/Android.mk b/libc/Android.mk
index 568cc94..a034c50 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -447,13 +447,7 @@
     libc_common_cflags += -DHAVE_ARM_TLS_REGISTER
   endif
 else # !arm
-  ifeq ($(TARGET_ARCH),x86)
-    libc_crt_target_cflags := -m32
-
-    # Enable recent IA friendly memory routines (such as for Atom)
-    # These will not work on the earlier x86 machines
-    libc_common_cflags += -mtune=i686 -DUSE_SSSE3 -DUSE_SSE2
-  endif # x86
+  libc_crt_target_cflags :=
 endif # !arm
 
 # Define some common includes