target/riscv: Relax vector register check in RISCV gdbstub

In current implementation, the gdbstub allows reading vector registers
only if V extension is supported. However, all vector extensions and
vector crypto extensions have the vector registers and they all depend
on Zve32x. The gdbstub should check for Zve32x instead.

Signed-off-by: Jason Chien <jason.chien@sifive.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Max Chou <max.chou@sifive.com>
Message-ID: <20240328022343.6871-4-jason.chien@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/gdbstub.c

@@ -338,7 +338,7 @@ void riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
                                  gdb_find_static_feature("riscv-32bit-fpu.xml"),
                                  0);
     }
-    if (env->misa_ext & RVV) {
+    if (cpu->cfg.ext_zve32x) {
         gdb_register_coprocessor(cs, riscv_gdb_get_vector,
                                  riscv_gdb_set_vector,
                                  ricsv_gen_dynamic_vector_feature(cs, cs->gdb_num_regs),