Remove MIPS support

build/toolchain/linux/BUILD.gn

Index: build/toolchain/linux/BUILD.gn
diff --git a/build/toolchain/linux/BUILD.gn b/build/toolchain/linux/BUILD.gn
index 79313f34b2532e1cf7d5cef641ca7bfdf2a6bb0a..7ad72ac34db467fe3ac15f8f2a1bde8fb94cc7be 100644
--- a/build/toolchain/linux/BUILD.gn
+++ b/build/toolchain/linux/BUILD.gn
@@ -126,17 +126,3 @@ gcc_toolchain("x64") {
   toolchain_os = "linux"
   is_clang = false
 }
-
-gcc_toolchain("mipsel") {
-  cc = "${compiler_prefix}${toolchain_prefix}gcc"
-  cxx = "${compiler_prefix}${toolchain_prefix}g++"
-  ar = "${toolchain_prefix}ar"
-  ld = cxx
-  readelf = "${toolchain_prefix}readelf"
-  nm = "${toolchain_prefix}nm"
-  strip = "${toolchain_prefix}strip"
-
-  toolchain_cpu = "${target_cpu}"
-  toolchain_os = "linux"
-  is_clang = is_clang
-}