laurel_sprout: remove TARGET_USES_64_BIT_BINDER

the TARGET_USES_64_BIT_BINDER option is deprecated and can be removed

Change-Id: I6b828da1fbcc8c054c5b35ff78c870a689f7ed9f
diff --git a/BoardConfig.mk b/BoardConfig.mk
index 6289606..de1bf61 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -23,8 +23,6 @@
 TARGET_2ND_CPU_VARIANT := generic
 TARGET_2ND_CPU_VARIANT_RUNTIME := cortex-a76
 
-TARGET_USES_64_BIT_BINDER := true
-
 BUILD_BROKEN_DUP_RULES := true
 
 MSMSTEPPE := trinket