arm: HVC and SMC encodings don't exist for M profile

M profile doesn't have the HVC or SMC encodings, so make them always
UNDEF rather than generating calls to helper functions that assume
A/R profile.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Message-id: 1487616072-9226-2-git-send-email-peter.maydell@linaro.org

target/arm/translate.c

@@ -10377,6 +10377,9 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
                     goto illegal_op;
 
                 if (insn & (1 << 26)) {
+                    if (arm_dc_feature(s, ARM_FEATURE_M)) {
+                        goto illegal_op;
+                    }
                     if (!(insn & (1 << 20))) {
                         /* Hypervisor call (v7) */
                         int imm16 = extract32(insn, 16, 4) << 12