cortex m3: add cortex_m3 reset_config cmd

This new cmd adds the ability to choose the Cortex-M3
reset method used.
It defaults to using SRST for reset if available otherwise
it falls back to using NVIC VECTRESET. This is known to work
on all cores.

Move any luminary specific reset handling to the stellaris cfg file.

Signed-off-by: Spencer Oliver <ntfreak@users.sourceforge.net>

src/target/cortex_m3.h

@@ -134,6 +134,13 @@ struct cortex_m3_dwt_comparator
 	uint32_t dwt_comparator_address;
 };
 
+enum cortex_m3_soft_reset_config
+{
+	CORTEX_M3_RESET_SRST,
+	CORTEX_M3_RESET_SYSRESETREQ,
+	CORTEX_M3_RESET_VECTRESET,
+};
+
 struct cortex_m3_common
 {
 	int common_magic;
@@ -158,6 +165,8 @@ struct cortex_m3_common
 	struct cortex_m3_dwt_comparator *dwt_comparator_list;
 	struct reg_cache *dwt_cache;
 
+	enum cortex_m3_soft_reset_config soft_reset_config;
+
 	struct armv7m_common armv7m;
 };