Suppress option to use custom optimization levels for architectures that do not support it

Kconfig

@@ -574,6 +574,10 @@ config DEBUG_SYMBOLS
 
 endmenu # Debug Options
 
+config ARCH_HAVE_CUSTOMOPT
+	bool
+	default n
+
 choice
 	prompt "Optimization Level"
 	default DEBUG_NOOPT if DEBUG_SYMBOLS
@@ -586,6 +590,7 @@ config DEBUG_NOOPT
 
 config DEBUG_CUSTOMOPT
 	bool "Custom Optimization"
+	depends on ARCH_HAVE_CUSTOMOPT
 	---help---
 		Select a custom debug level.  This is often helpful if you suspect an
 		optimization level error and want to lower the level of optimization.

arch/Kconfig

@@ -18,6 +18,7 @@ config ARCH_ARM
 	select ARCH_HAVE_INTERRUPTSTACK
 	select ARCH_HAVE_VFORK
 	select ARCH_HAVE_STACKCHECK
+	select ARCH_HAVE_CUSTOMOPT
 	---help---
 		The ARM architectures
 
@@ -25,6 +26,7 @@ config ARCH_AVR
 	bool "AVR"
 	select ARCH_NOINTC
 	select ARCH_HAVE_INTERRUPTSTACK
+	select ARCH_HAVE_CUSTOMOPT
 	---help---
 		Atmel 8-bit bit AVR and 32-bit AVR32 architectures
 
@@ -38,6 +40,7 @@ config ARCH_HC
 config ARCH_MIPS
 	bool "MIPS"
 	select ARCH_HAVE_INTERRUPTSTACK
+	select ARCH_HAVE_CUSTOMOPT
 	---help---
 		MIPS architectures (PIC32)