[General] More capability type handling (merge with others)

[General] More capability type handling (merge with others)

Teach more parts of GDB how to handle capabilities properly, add a function
to print capabilities in their natural format and initialize capability types
properly.

gdb/ChangeLog:

2020-10-20  Luis Machado  <luis.machado@arm.com>

	* c-typeprint.c (c_type_print_varspec_prefix)
	(c_type_print_varspec_suffix): Handle capability type.
	* dwarf2/read.c (read_base_type): Call init_capability_type for
	capabilities.
	* gdbtypes.c (init_capability_type): New function.
	(type_align): Handle capability type.
	(recursive_dump_type): Likewise.
	(arch_capability_type): New function.
	(gdbtypes_post_init): Call arch_capability_type for capability
	types.
	* gdbtypes.h (init_capability_type, arch_capability_type):  New
	prototypes.
	* valprint.c: Include gdbsupport/capability.h.
	(generic_value_print_capability): New function.
	(generic_value_print): Handle capability types.