Clean up the XML files for ARM

Clean up the XML files for ARM

This patch is move features/arm-*.xml to features/arm/, and it is based
on Terry's patch posted here
https://sourceware.org/ml/gdb-patches/2014-06/msg00794.html

One comment to Terry's patch is about losing "arm" prefix, and the new
patch fixes this problem.

gdb:

2016-10-05  Terry Guo  <terry.guo@arm.com>
	    Yao Qi  <yao.qi@linaro.org>

	* arm-tdep.c: Adjust includes.
	* features/Makefile (WHICH): Add "arm/" directory to arm
	target descriptions.
	(XMLTOC): Likewise.
	(arm/arm-with-iwmmxt.dat): Adjust the path for
	dependencies.
	* features/arm-core.xml: Moved to ...
	* features/arm/arm-core.xml: ... it.
	* features/arm-fpa.xml: Moved to ...
	* features/arm/arm-fpa.xml: ... it.
	* features/arm-m-profile.xml: Moved to ...
	* features/arm/arm-m-profile.xm: ... it.
	* features/arm-vfpv2.xml: Moved to ...
	* features/arm/arm-vfpv2.xm: ... it.
	* features/arm-vfpv3.xml: Moved to ...
	* features/arm/arm-vfpv3.xml: ... it.
	* features/arm-with-iwmmxt.c: Moved to ...
	* features/arm/arm-with-iwmmxt.c: ... it.
	* features/arm-with-iwmmxt.xml: Moved to ...
	* features/arm/arm-with-iwmmxt.xml: ... it.
	* features/arm-with-m-fpa-layout.c: Moved to ...
	* features/arm/arm-with-m-fpa-layout.c: ... it.
	* features/arm-with-m-fpa-layout.xml: Moved to ...
	* features/arm/arm-with-m-fpa-layout.xml: ... it.
	* features/arm-with-m-vfp-d16.c: Moved to ...
	* features/arm/arm-with-m-vfp-d16.c: ... it.
	* features/arm-with-m-vfp-d16.xml: Moved to ...
	* features/arm/arm-with-m-vfp-d16.xml: ... it.
	* features/arm-with-m.c: Moved to ...
	* features/arm/arm-with-m.c: ... it.
	* features/arm-with-m.xml: Moved to ...
	* features/arm/arm-with-m.xm: ... it.
	* features/arm-with-neon.c: Moved to ...
	* features/arm/arm-with-neon.c: ... it.
	* features/arm-with-neon.xml: Moved to ...
	* features/arm/arm-with-neon.xml: ... it.
	* features/arm-with-vfpv2.c: Moved to ...
	* features/arm/arm-with-vfpv2.c: ... it.
	* features/arm-with-vfpv2.xml: Moved to ...
	* features/arm/arm-with-vfpv2.xml: ... it.
	* features/arm-with-vfpv3.c: Moved to ...
	* features/arm/arm-with-vfpv3.c: ... it.
	* features/arm-with-vfpv3.xml: Moved to ...
	* features/arm/arm-with-vfpv3.xml: ... it.
	* features/xscale-iwmmxt.xml: Moved to ...
	* features/arm/xscale-iwmmxt.xml: ... it.

gdb/gdbserver:

2016-10-05  Terry Guo  <terry.guo@arm.com>
	    Yao Qi  <yao.qi@linaro.org>

	* Makefile.in: Adjust the path of rules.
	* configure.srv: Update the path of xml files.
	* regformats/arm-with-iwmmxt.dat: Regenerated.
	* regformats/arm-with-neon.dat: Likewise.
	* regformats/arm-with-vfpv2.dat: Likewise.
	* regformats/arm-with-vfpv3.dat Likewise.