Add CPU_ABIs for the second generic_arm64 architecture.

This was accidentally removed by commit 8dc227f482.
Breaks builds for apps that use gnustl_static for 32 bit compiles
on an arm64 target.

bug: 16951392

Change-Id: I89480943284944fd95543cccbf40a8de22852197

target/board/generic_arm64/BoardConfig.mk

@@ -22,6 +22,8 @@ TARGET_CPU_VARIANT := generic
 TARGET_CPU_ABI := arm64-v8a
 
 TARGET_2ND_ARCH := arm
+TARGET_2ND_CPU_ABI := armeabi-v7a
+TARGET_2ND_CPU_ABI2 := armeabi
 
 ifdef TARGET_BUILD_APPS
 # DO NOT USE
@@ -52,6 +54,7 @@ TARGET_2ND_ARCH_VARIANT := armv7-a-neon
 TARGET_2ND_CPU_VARIANT := cortex-a15
 endif
 
+
 TARGET_USES_64_BIT_BINDER := true
 
 # no hardware camera