m68k: add 68000 toolchain support

target/config/Config.in.cpu

@@ -796,6 +796,12 @@ config ADK_TARGET_CPU_M32R
 	depends on ADK_TARGET_ARCH_M32R
 
 # m68k
+config ADK_TARGET_CPU_M68K_68000
+	bool "68000"
+	select ADK_TARGET_SUPPORTS_THREADS
+	select ADK_TARGET_SUPPORTS_LT
+	depends on ADK_TARGET_ARCH_M68K
+
 config ADK_TARGET_CPU_M68K_68020
 	bool "68020"
 	select ADK_TARGET_SUPPORTS_THREADS
@@ -1984,6 +1990,7 @@ config ADK_TARGET_GCC_CPU
 	default "5373" if ADK_TARGET_CPU_CF_5373
 	default "5407" if ADK_TARGET_CPU_CF_5407
 	default "5475" if ADK_TARGET_CPU_CF_5475
+	default "68000" if ADK_TARGET_CPU_M68K_68000
 	default "68020" if ADK_TARGET_CPU_M68K_68020
 	default "68030" if ADK_TARGET_CPU_M68K_68030
 	default "68040" if ADK_TARGET_CPU_M68K_68040
@@ -2212,6 +2219,7 @@ config ADK_TARGET_CPU_TYPE
 	default "cf5373" if ADK_TARGET_CPU_CF_5373
 	default "cf5407" if ADK_TARGET_CPU_CF_5407
 	default "cf5475" if ADK_TARGET_CPU_CF_5475
+	default "68000" if ADK_TARGET_CPU_M68K_68000
 	default "68020" if ADK_TARGET_CPU_M68K_68020
 	default "68030" if ADK_TARGET_CPU_M68K_68030
 	default "68040" if ADK_TARGET_CPU_M68K_68040