ANDROID: build: fix build config kernel_dir

Change-Id: I88b87a9c85990b12dc8174349cfc14eddfb379d2
diff --git a/build.config.goldfish.mips b/build.config.goldfish.mips
index 5dcd8a1..8af53d2 100644
--- a/build.config.goldfish.mips
+++ b/build.config.goldfish.mips
@@ -3,7 +3,7 @@
 CROSS_COMPILE=mips64el-linux-android-
 DEFCONFIG=ranchu_defconfig
 EXTRA_CMDS=''
-KERNEL_DIR=goldfish
+KERNEL_DIR=common
 LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN=prebuilts/gcc/linux-x86/mips/mips64el-linux-android-4.9/bin
 FILES="
 vmlinux