* arm-tdep.c (struct arm_prologue_cache): Remove frameoffset.

	* arm-tdep.c (struct arm_prologue_cache): Remove frameoffset.
	(thumb_analyze_prologue): Move pv_area_store_would_trash call
	out of loop.  Do not set cache->frameoffset.
	(arm_scan_prologue): Use prologue-value mechanism.  Do not set
	frameoffset.  Simplify framesize.
	(arm_make_prologue_cache, arm_normal_frame_base): Do not use
	frameoffset.
	* arm-tdep.h (enum gdb_regnum): Add ARM_IP_REGNUM.