target/arm: optimize architecture flags

In target/arm.h the struct arm do contain 3 flags to retain architecture
version for some tweaks.
The proposal is to have only one enumerated flag 'arch' for the same purpose.

Change-Id: Ia5d5accfed8158ca21eb54af2fdea8e36f0266ae
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: http://openocd.zylin.com/6229
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

src/target/arm.h

@@ -60,6 +60,15 @@ enum arm_core_type {
 	ARM_CORE_TYPE_M_PROFILE,
 };
 
+/** ARM Architecture specifying the version and the profile */
+enum arm_arch {
+	ARM_ARCH_UNKNOWN,
+	ARM_ARCH_V4,
+	ARM_ARCH_V6M,
+	ARM_ARCH_V7M,
+	ARM_ARCH_V8M,
+};
+
 /**
  * Represent state of an ARM core.
  *
@@ -191,14 +200,8 @@ struct arm {
 	/** Record the current core state: ARM, Thumb, or otherwise. */
 	enum arm_state core_state;
 
-	/** Flag reporting unavailability of the BKPT instruction. */
-	bool is_armv4;
-
-	/** Flag reporting armv6m based core. */
-	bool is_armv6m;
-
-	/** Flag reporting armv8m based core. */
-	bool is_armv8m;
+	/** ARM architecture version */
+	enum arm_arch arch;
 
 	/** Floating point or VFP version, 0 if disabled. */
 	int arm_vfp_version;