target/sparc: Introduce sparc_cpu_register_gdb_regs() stub

Introduce sparc_cpu_register_gdb_regs() which we are going
to fill in the next commits.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20260219191955.83815-11-philmd@linaro.org>

target/sparc/cpu.c

@@ -897,6 +897,8 @@ static void sparc_cpu_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
+    sparc_cpu_register_gdb_regs(cs);
+
     qemu_init_vcpu(cs);
 
     scc->parent_realize(dev, errp);

target/sparc/cpu.h

@@ -586,6 +586,7 @@ hwaddr sparc_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 void sparc_cpu_do_interrupt(CPUState *cpu);
 int sparc_cpu_gdb_read_register(CPUState *cpu, GByteArray *buf, int reg);
 int sparc_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
+void sparc_cpu_register_gdb_regs(CPUState *cs);
 G_NORETURN void sparc_cpu_do_unaligned_access(CPUState *cpu, vaddr addr,
                                               MMUAccessType access_type,
                                               int mmu_idx,

target/sparc/gdbstub.c

@@ -215,3 +215,12 @@ int sparc_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
     return 8;
 #endif
 }
+
+void sparc_cpu_register_gdb_regs(CPUState *cs)
+{
+#if defined(TARGET_ABI32) || !defined(TARGET_SPARC64)
+    /* Not yet supported */
+#else
+    /* Not yet supported */
+#endif
+}