gdbserver/linux-low: turn 'supports_z_point_type' into a method

gdbserver/linux-low: turn 'supports_z_point_type' into a method

gdbserver/ChangeLog:
2020-04-02  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	Remove the 'supports_z_point_type' linux target op and let the
	concrete linux target define it by overriding the op declared in
	process_stratum_target.

	* linux-low.cc (linux_process_target::supports_z_point_type):
	Remove.
	* linux-low.h (struct linux_target_ops): Remove the op.
	(class linux_process_target) <supports_z_point_type>: Remove.
	* linux-x86-low.cc (class x86_target) <supports_z_point_type>:
	Declare.
	(x86_supports_z_point_type): Turn into...
	(x86_target::supports_z_point_type): ...this.
	(the_low_target): Remove the op field.
	* linux-aarch64-low.cc (class aarch64_target)
	<supports_z_point_type>: Declare.
	(aarch64_supports_z_point_type): Turn into...
	(aarch64_target::supports_z_point_type): ...this.
	(the_low_target): Remove the op field.
	* linux-arm-low.cc (class arm_target) <supports_z_point_type>:
	Declare.
	(arm_supports_z_point_type): Turn into...
	(arm_target::supports_z_point_type): ...this.
	(the_low_target): Remove the op field.
	* linux-crisv32-low.cc (class crisv32_target)
	<supports_z_point_type>: Declare.
	(cris_supports_z_point_type): Turn into...
	(crisv32_target::supports_z_point_type): ...this.
	(the_low_target): Remove the op field.
	* linux-mips-low.cc (class mips_target) <supports_z_point_type>:
	Declare.
	(mips_supports_z_point_type): Turn into...
	(mips_target::supports_z_point_type): ...this.
	(the_low_target): Remove the op field.
	* linux-ppc-low.cc (class ppc_target) <supports_z_point_type>:
	Declare.
	(ppc_supports_z_point_type): Turn into...
	(ppc_target::supports_z_point_type): ...this.
	(the_low_target): Remove the op field.
	* linux-s390-low.cc (class s390_target) <supports_z_point_type>:
	Declare.
	(s390_supports_z_point_type): Turn into...
	(s390_target::supports_z_point_type): ...this.
	(the_low_target): Remove the op field.
	* linux-bfin-low.cc (the_low_target): Remove the op field.
	* linux-m32r-low.cc (the_low_target): Ditto.
	* linux-m68k-low.cc (the_low_target): Ditto.
	* linux-sh-low.cc (the_low_target): Ditto.
	* linux-sparc-low.cc (the_low_target): Ditto.
	* linux-tic6x-low.cc (the_low_target): Ditto.
	* linux-tile-low.cc (the_low_target): Ditto.
	* linux-xtensa-low.cc (the_low_target): Ditto.