gdbserver: Suffix generated C files with -generated

gdbserver: Suffix generated C files with -generated

I noticed that there were some missing files in gdbserver's gitignore
(some generated register format .c files).  Of course the easy fix would
be to add those files to .gitignore, but I think we can do a better job,
so that we don't have to worry about adding generated files to
.gitignore or the clean Makefile target.

I suggest naming all generated source files -generated.c.  This way, we
can use a single rule in .gitignore and do a "rm -f *-generated.c" to
clean them up.

New in v2:

  - Don't rename version.o and xml-builtin.o

gdb/gdbserver/ChangeLog:

	* .gitignore: Remove generated files, replace with wildcard.
	* (clean): Replace removal of generated files with wildcard.
	(version.c): Replace with...
	(version-generated.c): ...this.
	(xml-builtin.c): Replace with...
	(xml-builtin-generated.c): ...this.
	(%-ipa.o: %-generated.c, %.o: %-generated.c): New rules.
	(%.c: *regformats*): Replace with...
	(%-generated.c: *regformats*): ...this.