armv7m: detect floating point feature

This patch add fp feature detection on cortex-m4.

Change-Id: I99e9d1bf5534630a22b8ad9c878165683db2d0ba
Signed-off-by: Mathias K <kesmtp@freenet.de>
Reviewed-on: http://openocd.zylin.com/524
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

src/target/armv7m.c

@@ -578,6 +578,7 @@ int armv7m_init_arch_info(struct target *target, struct armv7m_common *armv7m)
 	struct arm *arm = &armv7m->arm;
 
 	armv7m->common_magic = ARMV7M_COMMON_MAGIC;
+	armv7m->fp_feature = FP_NONE;
 
 	arm->core_type = ARM_MODE_THREAD;
 	arm->arch_info = armv7m;