msm8953-common: Set TARGET_2ND_ARCH_VARIANT to armv8-a

Setting TARGET_2ND_ARCH_VARIANT to armv8-a, instead of armv7-a-neon,
can silence the related warning during build.

Bug: 68012286
Change-Id: I18ae3aa985fd6bff11f043a155f3685d9f6644b8

BoardConfigCommon.mk

@@ -26,7 +26,7 @@ TARGET_CPU_ABI2 :=
 TARGET_CPU_VARIANT := generic
 
 TARGET_2ND_ARCH := arm
-TARGET_2ND_ARCH_VARIANT := armv7-a-neon
+TARGET_2ND_ARCH_VARIANT := armv8-a
 TARGET_2ND_CPU_ABI := armeabi-v7a
 TARGET_2ND_CPU_ABI2 := armeabi
 TARGET_2ND_CPU_VARIANT := cortex-a53