MIPS: Move register conventions out of the IC classes.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index a93e31d8beb0d02871891e9eac1d23322e9cfb1b..6f449f6fc8993034c1cae7f2b4458dcc4e855083 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1071,9 +1071,10 @@ source_set("v8_base") {
       "src/ic/mips/handler-compiler-mips.cc",
       "src/ic/mips/ic-mips.cc",
       "src/ic/mips/ic-compiler-mips.cc",
+      "src/ic/mips/ic-conventions-mips.cc",
       "src/ic/mips/stub-cache-mips.cc",
     ]
-  } else if (v8_target_arch == "mips64") {
+  } else if (v8_target_arch == "mips64el") {
     sources += [
       "src/mips64/assembler-mips64.cc",
       "src/mips64/assembler-mips64.h",
@@ -1107,6 +1108,7 @@ source_set("v8_base") {
       "src/ic/mips64/handler-compiler-mips64.cc",
       "src/ic/mips64/ic-mips64.cc",
       "src/ic/mips64/ic-compiler-mips64.cc",
+      "src/ic/mips64/ic-conventions-mips64.cc",
       "src/ic/mips64/stub-cache-mips64.cc",
     ]
   }