[mips] Make Static a default relocation model for MIPS codegen

This change follows up defaults for GCC and Clang, so LLVM does not differ
from them. While number of the test files are touched with this change, they
all keep the old (expected) behaviour with the explicit option:
"-relocation-model=pic"
The tests that have not been touched are insensitive to relocation model.

Differential Revision: http://reviews.llvm.org/D17995

llvm-svn: 265949
diff --git a/llvm/test/CodeGen/Mips/i64arg.ll b/llvm/test/CodeGen/Mips/i64arg.ll
index 5b2d135..22a0c1f 100644
--- a/llvm/test/CodeGen/Mips/i64arg.ll
+++ b/llvm/test/CodeGen/Mips/i64arg.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=mips < %s | FileCheck %s
+; RUN: llc -march=mips -relocation-model=pic < %s | FileCheck %s
 
 define void @f1(i64 %ll1, float %f, i64 %ll, i32 %i, float %f2) nounwind {
 entry: