Remove references/use of ARCH_X86_HAVE_* in frameworks/rs.

Bug: 11048298

These SSE-related defines are unnecessary because all x86 Android devices
have these features. We switch all the checks to __i386__ instead.

This also fixes an issue where non-ARM bitcode files were being created with
the ARM defines present. This is problematic when we then try to do things
that would be arch-specific (i.e. the presence of SSE-enabled functions for
clamp(), ...).

This also cleans up the different target architecture specified in the x86
bitcode files so that they match the platform target (i686-unknown-linux).

Change-Id: I4776bbdce360de26e8a00e05d2cb19341d94a173
diff --git a/cpu_ref/rsCpuScript.cpp b/cpu_ref/rsCpuScript.cpp
index 0669326..c956f43 100644
--- a/cpu_ref/rsCpuScript.cpp
+++ b/cpu_ref/rsCpuScript.cpp
@@ -396,8 +396,8 @@
         return false;
     }
 
-#if defined(ARCH_X86_HAVE_SSE2)
-    // SSE2- or above capable devices will use an optimized library.
+#if defined(__i386__)
+    // x86 devices will use an optimized library.
     core_lib = bcc::RSInfo::LibCLCoreX86Path;
 #endif