Set 32bits Legacy GSI to be 32bits binder

The binder interface bitness is always 64bits from P.
To keep 32bits binder interface for Legacy GSI, we need to explict
configure it.

Bug: 122282239
Test: lunch aosp_arm_ab-userdebug; make -j
Change-Id: I90b45adb52c398d1c0cf3f877199f9dd1e0b3f86
diff --git a/target/board/treble_common_32.mk b/target/board/treble_common_32.mk
index b66c41e..e8bad08 100644
--- a/target/board/treble_common_32.mk
+++ b/target/board/treble_common_32.mk
@@ -15,3 +15,6 @@
 #
 
 include build/make/target/board/treble_common.mk
+
+# Legacy GSI keeps 32 bits binder for 32 bits CPU Arch
+TARGET_USES_64_BIT_BINDER := false