target/mips: Introduce cpu_supports_isa() taking CPUMIPSState argument

Introduce cpu_supports_isa() which takes a CPUMIPSState
argument, more useful at runtime when the CPU is created
(no need to call the extensive object_class_by_name()).

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201207215257.4004222-3-f4bug@amsat.org>

target/mips/cpu.c

@@ -310,3 +310,8 @@ MIPSCPU *mips_cpu_create_with_clock(const char *cpu_type, Clock *cpu_refclk)
 
     return MIPS_CPU(cpu);
 }
+
+bool cpu_supports_isa(const CPUMIPSState *env, uint64_t isa_mask)
+{
+    return (env->cpu_model->insn_flags & isa_mask) != 0;
+}