armv7m: use consistent arm.cpsr member

We already set cpsr in armv7m_build_reg_cache, so lets use it for all other
accesses to this field.

Change-Id: I19b3b21ecf1571bbea12e1be664845e6544f6fa1
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/1539
Tested-by: jenkins

src/target/hla_target.c

@@ -427,7 +427,7 @@ static int adapter_debug_entry(struct target *target)
 	/* make sure we clear the vector catch bit */
 	adapter->layout->api->write_debug_reg(adapter->fd, DCB_DEMCR, TRCENA);
 
-	r = arm->core_cache->reg_list + ARMV7M_xPSR;
+	r = arm->cpsr;
 	xPSR = buf_get_u32(r->value, 0, 32);
 
 	/* Are we in an exception handler */