[docs] Add Mips as a supported architecture in GettingStarted.rst

Patch by Miloš Stojanović

Differential Revision: https://reviews.llvm.org/D69380
diff --git a/llvm/docs/GettingStarted.rst b/llvm/docs/GettingStarted.rst
index 426bb76..963de6f 100644
--- a/llvm/docs/GettingStarted.rst
+++ b/llvm/docs/GettingStarted.rst
@@ -117,6 +117,7 @@
 Linux              x86\ :sup:`1`         GCC, Clang
 Linux              amd64                 GCC, Clang
 Linux              ARM                   GCC, Clang
+Linux              Mips                  GCC, Clang
 Linux              PowerPC               GCC, Clang
 Solaris            V9 (Ultrasparc)       GCC
 FreeBSD            x86\ :sup:`1`         GCC, Clang