gdbserver/linux-low: turn '{collect, supply}_ptrace_register' into methods

gdbserver/linux-low: turn '{collect, supply}_ptrace_register' into methods

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

	Turn the 'collect_ptrace_register' and 'supply_ptrace_register'
	linux target ops into methods of linux_process_target.

	* linux-low.h (struct linux_target_ops): Remove the ops.
	(class linux_process_target) <low_collect_ptrace_register>
	<low_store_ptrace_register>: Declare.
	* linux-low.cc (linux_process_target::low_collect_ptrace_register)
	(linux_process_target::low_supply_ptrace_register): Define.

	Update the callers below.

	(linux_process_target::fetch_register)
	(linux_process_target::store_register)

	* linux-x86-low.cc (the_low_target): Remove the op fields.
	* linux-aarch64-low.cc (the_low_target): Ditto.
	* linux-arm-low.cc (the_low_target): Ditto.
	* linux-bfin-low.cc (the_low_target): Ditto.
	* linux-crisv32-low.cc (the_low_target): Ditto.
	* 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.
	* linux-mips-low.cc (class mips_target)
	<low_collect_ptrace_register>
	<low_supply_ptrace_register>: Declare.
	(mips_collect_ptrace_register): Turn into ...
	(mips_target::low_collect_ptrace_register): ...this.
	(mips_supply_ptrace_register): Turn into...
	(mips_target::low_supply_ptrace_register): ...this.
	(the_low_target): Remove the op fields.
	* linux-ppc-low.cc (class ppc_target)
	<low_collect_ptrace_register>
	<low_supply_ptrace_register>: Declare.
	(ppc_collect_ptrace_register): Turn into ...
	(ppc_target::low_collect_ptrace_register): ...this.
	(ppc_supply_ptrace_register): Turn into ...
	(ppc_target::low_supply_ptrace_register): ...this.
	(ppc_fill_gregset): Update for the calls to
	low_collect_ptrace_register.
	(the_low_target): Remove the op fields.
	* linux-s390-low.cc (class s390_target)
	<low_collect_ptrace_register>
	<low_supply_ptrace_register>: Declare.
	(s390_collect_ptrace_register): Turn into ...
	(s390_target::low_collect_ptrace_register): ...this.
	(s390_supply_ptrace_register): Turn into ...
	(s390_target::low_supply_ptrace_register): ...this.
	(s390_fill_gregset): Update for the calls to
	low_collect_ptrace_register.
	(the_low_target): Remove the op fields.