gdbstub: Make syscall_complete/[gs]et_reg target-agnostic typedefs

Prototypes using gdb_syscall_complete_cb() or gdb_?et_reg_cb()
don't depend on "cpu.h", thus are not target-specific.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20221214143659.62133-1-philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230302190846.2593720-4-alex.bennee@linaro.org>
Message-Id: <20230303025805.625589-4-richard.henderson@linaro.org>

include/exec/gdbstub.h

@@ -71,9 +71,6 @@ struct gdb_timeval {
   uint64_t tv_usec;   /* microsecond */
 } QEMU_PACKED;
 
-#ifdef NEED_CPU_H
-#include "cpu.h"
-
 typedef void (*gdb_syscall_complete_cb)(CPUState *cpu, uint64_t ret, int err);
 
 /**
@@ -126,6 +123,7 @@ int gdb_handlesig(CPUState *, int);
 void gdb_signalled(CPUArchState *, int);
 void gdbserver_fork(CPUState *);
 #endif
+
 /* Get or set a register.  Returns the size of the register.  */
 typedef int (*gdb_get_reg_cb)(CPUArchState *env, GByteArray *buf, int reg);
 typedef int (*gdb_set_reg_cb)(CPUArchState *env, uint8_t *buf, int reg);
@@ -133,6 +131,9 @@ void gdb_register_coprocessor(CPUState *cpu,
                               gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg,
                               int num_regs, const char *xml, int g_pos);
 
+#ifdef NEED_CPU_H
+#include "cpu.h"
+
 /*
  * The GDB remote protocol transfers values in target byte order. As
  * the gdbstub may be batching up several register values we always