cpu: Introduce CPUClass::gdb_{read,write}_register()

Completes migration of target-specific code to new target-*/gdbstub.c.

Acked-by: Michael Walle <michael@walle.cc> (for lm32)
Acked-by: Max Filippov <jcmvbkbc@gmail.com> (for xtensa)
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/target-openrisc/cpu.c b/target-openrisc/cpu.c
index 9b042e1..aa269fb 100644
--- a/target-openrisc/cpu.c
+++ b/target-openrisc/cpu.c
@@ -155,6 +155,8 @@
     cc->do_interrupt = openrisc_cpu_do_interrupt;
     cc->dump_state = openrisc_cpu_dump_state;
     cc->set_pc = openrisc_cpu_set_pc;
+    cc->gdb_read_register = openrisc_cpu_gdb_read_register;
+    cc->gdb_write_register = openrisc_cpu_gdb_write_register;
 #ifndef CONFIG_USER_ONLY
     cc->get_phys_page_debug = openrisc_cpu_get_phys_page_debug;
     dc->vmsd = &vmstate_openrisc_cpu;