arc: use gcc10 as default

target/config/Config.in.compiler

@@ -18,10 +18,10 @@ default ADK_TOOLCHAIN_GCC_METAG if ADK_TARGET_ARCH_METAG
 default ADK_TOOLCHAIN_GCC_NDS32 if ADK_TARGET_ARCH_NDS32
 default ADK_TOOLCHAIN_GCC_7 if ADK_TARGET_CPU_ARM_ARM11MPCORE
 default ADK_TOOLCHAIN_GCC_7 if ADK_TARGET_CPU_ARM_CORTEX_A53
-default ADK_TOOLCHAIN_GCC_9 if ADK_TARGET_ARCH_ARC
 default ADK_TOOLCHAIN_GCC_9 if ADK_TARGET_ARCH_CSKY
 default ADK_TOOLCHAIN_GCC_9 if ADK_TARGET_ARCH_HPPA
 default ADK_TOOLCHAIN_GCC_9 if ADK_TARGET_ARCH_OR1K
+default ADK_TOOLCHAIN_GCC_10 if ADK_TARGET_ARCH_ARC
 default ADK_TOOLCHAIN_GCC_8
 
 config ADK_TOOLCHAIN_GCC_GIT
@@ -38,6 +38,7 @@ config ADK_TOOLCHAIN_GCC_10
 
 config ADK_TOOLCHAIN_GCC_9
 	bool "9.3.0"
+	depends on !ADK_TARGET_ARCH_ARC
 	depends on !ADK_TARGET_ARCH_AVR32
 	depends on !ADK_TARGET_ARCH_METAG
 	depends on !ADK_TARGET_ARCH_NDS32