gdbserver: simply copy the pointer in 'set_target_ops'

gdbserver: simply copy the pointer in 'set_target_ops'

The 'set_target_ops' function takes a target op vector and creates a
clone of it via XNEW and memcpy.  This is not necessary.  'the_target'
is a singleton, and the argument that is passed to 'set_target_ops' is
always the address of a global, static object.  Therefore, update the
implementation to simply copy the pointer.

gdbserver/ChangeLog:
2020-02-20  Pedro Alves  <palves@redhat.com>

	* target.cc (set_target_ops): Simply copy the given target pointer
	instead of creating a copy of the pointed object.