v8.gyp: Fix mips (big-endian) build.

src/v8.gyp

Index: src/v8.gyp
diff --git a/src/v8.gyp b/src/v8.gyp
index fce1ed9a379f8621e09ee9b9ebcf30689d76e046..3abd090d01d473edc0ef618e1ed685f37364b888 100644
--- a/src/v8.gyp
+++ b/src/v8.gyp
@@ -1274,10 +1274,8 @@
           'toolsets': ['target'],
         }],
         ['want_separate_host_toolset_mkpeephole==1', {
-          'toolsets': ['host', 'target'],
           'dependencies': ['mkpeephole#host'],
         }, {
-          'toolsets': ['target'],
           'dependencies': ['mkpeephole'],
         }],
         ['v8_target_arch=="arm"', {