Fixups after llvm rebase

Clang now generates a SHF_MERGE section that is rejected by GNU as on
Mips64. Change to use integrated assembler for Mips and Mips64.

Bug: 37423073
Test: external/clang/build.py
Change-Id: I8eae5cf370b930119eb6892db960f5f70777312f
diff --git a/cc/config/mips_device.go b/cc/config/mips_device.go
index f5b14bd..ccd60d6 100644
--- a/cc/config/mips_device.go
+++ b/cc/config/mips_device.go
@@ -52,7 +52,7 @@
 
 	mipsClangCflags = append(mipsCflags, []string{
 		"-fPIC",
-		"-fno-integrated-as",
+		"-fintegrated-as",
 	}...)
 
 	mipsCppflags = []string{