target/microblaze: Prefer fast cpu_env() over slower CPU QOM cast macro

Mechanical patch produced running the command documented
in scripts/coccinelle/cpu_env.cocci_template header.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240129164514.73104-18-philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
diff --git a/target/microblaze/gdbstub.c b/target/microblaze/gdbstub.c
index eb168d1..09d74e1 100644
--- a/target/microblaze/gdbstub.c
+++ b/target/microblaze/gdbstub.c
@@ -110,9 +110,8 @@
 
 int mb_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
 {
-    MicroBlazeCPU *cpu = MICROBLAZE_CPU(cs);
     CPUClass *cc = CPU_GET_CLASS(cs);
-    CPUMBState *env = &cpu->env;
+    CPUMBState *env = cpu_env(cs);
     uint32_t tmp;
 
     if (n > cc->gdb_num_core_regs) {