gdb, gdbserver: remove ARM regdat files

gdb, gdbserver: remove ARM regdat files

This patch removes the leftover regformats .dat files for the arm
architecture.  There are no longer relevant, since the arm architecture
has been converted to use feature-based target-descriptions.  These .dat
files are used by GDBserver ports that still use static target
descriptions.

These .dat files are generated from corresponding .xml files in the
features directory.  And since the corresponding .xml files for these
arm .dat files don't exist anymore, it is impossible to re-generated
them.  If you delete these .dat files and type "make" in the features
directory, you'll get:

  make: *** No rule to make target '../regformats/arm/arm-with-iwmmxt.dat', needed by 'all'.  Stop.

So it removes the entries in the `WHICH` variable of
gdb/features/Makefile.

Finally, it removes the rule in gdbserver/Makefile to generate .cc files
from `../gdb/regformats/arm/%.dat`.

gdb/ChangeLog:

	* features/Makefile (WHICH): Remove arm files.
	* regformats/arm/arm-with-iwmmxt.dat: Remove.
	* regformats/arm/arm-with-neon.dat: Remove.
	* regformats/arm/arm-with-vfpv2.dat: Remove.
	* regformats/arm/arm-with-vfpv3.dat: Remove.

gdbserver/ChangeLog:

	* Makefile.in (%-generated.cc: ../gdb/regformats/arm/%.dat):
	Remove.

Change-Id: I3b7d989c50e2cb92235c1f7c7071a26839d84c78