Make mainline targets use generic arch variant

mainline_system always has a generic variant, and this brings
blueline_mainline closer to that.

Bug: 80410283
Test: lunch blueline; lunch blueline_mainline
Change-Id: Ib8ea29cae710bef4d05718043b1fa490c62f4526

BoardConfig-common.mk

diff --git a/BoardConfig-common.mk b/BoardConfig-common.mk
index 27ae24e..0214766 100644
--- a/BoardConfig-common.mk
+++ b/BoardConfig-common.mk
@@ -20,16 +20,28 @@
 TARGET_NO_BOOTLOADER := true
 
 TARGET_ARCH := arm64
+ifeq (,$(filter %_mainline,$(TARGET_PRODUCT)))
 TARGET_ARCH_VARIANT := armv8-2a
+else
+TARGET_ARCH_VARIANT := armv8-a
+endif
 TARGET_CPU_ABI := arm64-v8a
 TARGET_CPU_ABI2 :=
+ifeq (,$(filter %_mainline,$(TARGET_PRODUCT)))
 TARGET_CPU_VARIANT := cortex-a75
+else
+TARGET_CPU_VARIANT := generic
+endif
 
 TARGET_2ND_ARCH := arm
 TARGET_2ND_ARCH_VARIANT := armv8-a
 TARGET_2ND_CPU_ABI := armeabi-v7a
 TARGET_2ND_CPU_ABI2 := armeabi
+ifeq (,$(filter %_mainline,$(TARGET_PRODUCT)))
 TARGET_2ND_CPU_VARIANT := cortex-a75
+else
+TARGET_2ND_CPU_VARIANT := generic
+endif
 
 TARGET_BOARD_COMMON_PATH := device/google/crosshatch/sdm845