Break forced selection of CPU_CORTEX_M3

Makes the ARM CPU type a choice between CPU_CORTEX_M3 and CPU_CORTEX_M4
(similar to the choice of processor for x86). This completes the breaking
of the forced selection of CPU_CORTEX_M3 when CPU_CORTEX_M4 chosen, thereby
making CPU_CORTEX_M3_M4 the true umbrella option for the Cortex M3/M4
processors.

Change-Id: I1d1f39352d85a5848b13102ceb8365c7dede0959
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>

arch/arm/bsp/CortexM/Kconfig

@@ -54,21 +54,22 @@ config CPU_CORTEX_M3_M4
 	help
 	This option signifies the use of either a Cortex-M3 or Cortex-M4 CPU.
 
+choice
+prompt "ARM Cortex M3 or M4 Processor"
+default CPU_CORTEX_M4
+
 config CPU_CORTEX_M3
-	# omit prompt to signify a "hidden" option
 	bool "ARM Cortex-M3"
-	default n
 	select CPU_CORTEX_M3_M4
 	help
-	This option signifies the use of a Cortex-M3+ CPU
+	This option signifies the use of a Cortex-M3 CPU
 
 config CPU_CORTEX_M4
-	# omit prompt to signify a "hidden" option
 	bool "ARM Cortex-M4"
-	default n
-	select CPU_CORTEX_M3
+	select CPU_CORTEX_M3_M4
 	help
 	This option signifies the use of a Cortex-M4 CPU
+endchoice
 
 endmenu
 

arch/arm/configs/micro_fsl_frdm_k64f_defconfig

@@ -85,7 +85,7 @@ CONFIG_BSP_FSL_FRDM_K64F=y
 CONFIG_CPU_CORTEX=y
 CONFIG_CPU_CORTEX_M=y
 CONFIG_CPU_CORTEX_M3_M4=y
-CONFIG_CPU_CORTEX_M3=y
+# CONFIG_CPU_CORTEX_M3 is not set
 CONFIG_CPU_CORTEX_M4=y
 
 #

arch/arm/configs/nano_fsl_frdm_k64f_defconfig

@@ -64,7 +64,7 @@ CONFIG_BSP_FSL_FRDM_K64F=y
 CONFIG_CPU_CORTEX=y
 CONFIG_CPU_CORTEX_M=y
 CONFIG_CPU_CORTEX_M3_M4=y
-CONFIG_CPU_CORTEX_M3=y
+# CONFIG_CPU_CORTEX_M3 is not set
 CONFIG_CPU_CORTEX_M4=y
 
 #

arch/arm/defconfig

@@ -85,7 +85,7 @@ CONFIG_BSP_FSL_FRDM_K64F=y
 CONFIG_CPU_CORTEX=y
 CONFIG_CPU_CORTEX_M=y
 CONFIG_CPU_CORTEX_M3_M4=y
-CONFIG_CPU_CORTEX_M3=y
+# CONFIG_CPU_CORTEX_M3 is not set
 CONFIG_CPU_CORTEX_M4=y
 
 #