build: mips: add default compilation options

MIPS targets should be compiled with no position independent code
allowed, as the generated image often does not support short range
components reference.

BUG=chrome-os-partner:31438
TEST=with the rest of the patches included MIPS board urara builds
     successfully

Change-Id: I637dd44eb565447c18b2c3cdb022d0933c52fd20
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/215677
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

util/xcompile/xcompile

@@ -116,7 +116,8 @@ detect_special_flags() {
 		testcc "$CC" "$CFLAGS" && CFLAGS="$CFLAGS"
 		;;
 	mipsel )
-		testcc "$CC" "$CFLAGS"
+		testcc "$CC" "$CFLAGS -mno-abicalls -fno-pic" && \
+                  CFLAGS+=" -mno-abicalls -fno-pic"
 		;;
 	esac
 }